svn commit: r40783 - head/en_US.ISO8859-1/books/handbook/serialcomms
Dru Lavigne
dru at FreeBSD.org
Mon Jan 28 15:15:47 UTC 2013
Author: dru
Date: Mon Jan 28 15:15:46 2013
New Revision: 40783
URL: http://svnweb.freebsd.org/changeset/doc/40783
Log:
White space fix only. Translators can ignore.
Approved by: bcr (mentor)
Modified:
head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml
Modified: head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml
==============================================================================
--- head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml Mon Jan 28 15:14:36 2013 (r40782)
+++ head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml Mon Jan 28 15:15:46 2013 (r40783)
@@ -13,12 +13,13 @@
<indexterm><primary>serial communications</primary></indexterm>
- <para>&unix; has always had support for serial communications. In fact,
- the very first &unix; machines relied on serial lines for user input
- and output. Things have changed a lot from the days when the average
- <quote>terminal</quote> consisted of a 10-character-per-second serial
- printer and a keyboard. This chapter will cover some of the ways in
- which FreeBSD uses serial communications.</para>
+ <para>&unix; has always had support for serial communications. In
+ fact, the very first &unix; machines relied on serial lines for
+ user input and output. Things have changed a lot from the days
+ when the average <quote>terminal</quote> consisted of a
+ 10-character-per-second serial printer and a keyboard. This
+ chapter will cover some of the ways in which FreeBSD uses serial
+ communications.</para>
<para>After reading this chapter, you will know:</para>
@@ -52,9 +53,9 @@
linkend="basics"/>).</para>
</listitem>
<listitem>
- <para>Have access to the technical manual for the serial hardware
- (modem or multi-port card) that you would like to use with
- FreeBSD.</para>
+ <para>Have access to the technical manual for the serial
+ hardware (modem or multi-port card) that you would like to
+ use with FreeBSD.</para>
</listitem>
</itemizedlist>
</sect1>
@@ -103,7 +104,8 @@
<listitem>
<indexterm><primary>DCE</primary></indexterm>
- <para>Data Communications Equipment — your modem</para>
+ <para>Data Communications Equipment — your
+ modem</para>
</listitem>
</varlistentry>
@@ -113,7 +115,8 @@
<listitem>
<indexterm><primary>RS-232C cables</primary></indexterm>
- <para>EIA standard for hardware serial communications</para>
+ <para>EIA standard for hardware serial
+ communications</para>
</listitem>
</varlistentry>
</variablelist>
@@ -122,18 +125,18 @@
does not use the term <quote>baud</quote>. Baud refers to the
number of electrical state transitions that may be made in a
period of time, while <quote>bps</quote> (bits per second) is
- the <emphasis>correct</emphasis> term to use (at least it does not
- seem to bother the curmudgeons quite as much).</para>
+ the <emphasis>correct</emphasis> term to use (at least it does
+ not seem to bother the curmudgeons quite as much).</para>
</sect2>
<sect2 id="serial-cables-ports">
<title>Cables and Ports</title>
<para>To connect a modem or terminal to your FreeBSD system, you
- will need a serial port on your computer and the proper cable to
- connect to your serial device. If you are already familiar with your
- hardware and the cable it requires, you can safely skip this
- section.</para>
+ will need a serial port on your computer and the proper cable
+ to connect to your serial device. If you are already familiar
+ with your hardware and the cable it requires, you can safely
+ skip this section.</para>
<sect3 id="term-cables">
<title>Cables</title>
@@ -141,8 +144,8 @@
<para>There are several different kinds of serial cables. The
two most common types for our purposes are null-modem cables
and standard (<quote>straight</quote>) RS-232 cables. The
- documentation for your hardware should describe the type of cable
- required.</para>
+ documentation for your hardware should describe the type of
+ cable required.</para>
<sect4 id="term-cables-null">
<title>Null-modem Cables</title>
@@ -152,20 +155,21 @@
</indexterm>
<para>A null-modem cable passes some signals, such as
- <quote>Signal Ground</quote>, straight through, but switches other
- signals. For example, the <quote>Transmitted Data</quote> pin on
- one end goes to the <quote>Received Data</quote> pin on the other
- end.</para>
-
- <para>You can also construct your own null-modem cable for use with
- terminals (e.g., for quality purposes). This table shows the
- RS-232C <link linkend="serialcomms-signal-names">signals</link>
- and the pin numbers on a DB-25 connector. Note that the standard
- also calls for a straight-through pin 1 to pin 1
- <emphasis>Protective Ground</emphasis> line, but it is often
- omitted. Some terminals work OK using only pins 2, 3 and 7,
- while others require different configurations than the examples
- shown below.</para>
+ <quote>Signal Ground</quote>, straight through, but
+ switches other signals. For example, the
+ <quote>Transmitted Data</quote> pin on one end goes to the
+ <quote>Received Data</quote> pin on the other end.</para>
+
+ <para>You can also construct your own null-modem cable for
+ use with terminals (e.g., for quality purposes). This
+ table shows the RS-232C <link
+ linkend="serialcomms-signal-names">signals</link>
+ and the pin numbers on a DB-25 connector. Note that the
+ standard also calls for a straight-through pin 1 to pin 1
+ <emphasis>Protective Ground</emphasis> line, but it is
+ often omitted. Some terminals work OK using only pins 2,
+ 3 and 7, while others require different configurations
+ than the examples shown below.</para>
<table frame="none" pgwide="1">
<title>DB-25 to DB-25 Null-Modem Cable</title>
@@ -257,7 +261,8 @@
</tgroup>
</table>
- <para>Here are two other schemes more common nowadays.</para>
+ <para>Here are two other schemes more common
+ nowadays.</para>
<table frame="none" pgwide="1">
<title>DB-9 to DB-9 Null-Modem Cable</title>
@@ -441,87 +446,92 @@
<note>
<para>When one pin at one end connects to a pair of pins
- at the other end, it is usually implemented with one short
- wire between the pair of pins in their connector and a
- long wire to the other single pin.</para>
+ at the other end, it is usually implemented with one
+ short wire between the pair of pins in their connector
+ and a long wire to the other single pin.</para>
</note>
- <para>The above designs seems to be the most popular. In another
- variation (explained in the book <emphasis>RS-232 Made
- Easy</emphasis>) SG connects to SG, TD connects to RD, RTS and
- CTS connect to DCD, DTR connects to DSR, and vice-versa.</para>
+ <para>The above designs seems to be the most popular. In
+ another variation (explained in the book <emphasis>RS-232
+ Made Easy</emphasis>) SG connects to SG, TD connects to
+ RD, RTS and CTS connect to DCD, DTR connects to DSR, and
+ vice-versa.</para>
</sect4>
<sect4 id="term-cables-std">
<title>Standard RS-232C Cables</title>
+
<indexterm><primary>RS-232C cables</primary></indexterm>
- <para>A standard serial cable passes all of the RS-232C signals
- straight through. That is, the <quote>Transmitted Data</quote>
- pin on one end of the cable goes to the
- <quote>Transmitted Data</quote> pin on the other end. This is
- the type of cable to use to connect a modem to your FreeBSD
- system, and is also appropriate for some terminals.</para>
+ <para>A standard serial cable passes all of the RS-232C
+ signals straight through. That is, the <quote>Transmitted
+ Data</quote> pin on one end of the cable goes to the
+ <quote>Transmitted Data</quote> pin on the other end.
+ This is the type of cable to use to connect a modem to
+ your FreeBSD system, and is also appropriate for some
+ terminals.</para>
</sect4>
</sect3>
<sect3 id="term-ports">
<title>Ports</title>
- <para>Serial ports are the devices through which data is transferred
- between the FreeBSD host computer and the terminal. This section
- describes the kinds of ports that exist and how they are addressed
- in FreeBSD.</para>
+ <para>Serial ports are the devices through which data is
+ transferred between the FreeBSD host computer and the
+ terminal. This section describes the kinds of ports that
+ exist and how they are addressed in FreeBSD.</para>
<sect4 id="term-portkinds">
<title>Kinds of Ports</title>
- <para>Several kinds of serial ports exist. Before you purchase or
- construct a cable, you need to make sure it will fit the ports on
- your terminal and on the FreeBSD system.</para>
-
- <para>Most terminals will have DB-25 ports. Personal computers,
- including PCs running FreeBSD, will have DB-25 or DB-9 ports. If
- you have a multiport serial card for your PC, you may have RJ-12 or
- RJ-45 ports.</para>
-
- <para>See the documentation that accompanied the hardware for
- specifications on the kind of port in use. A visual inspection of
- the port often works too.</para>
+ <para>Several kinds of serial ports exist. Before you
+ purchase or construct a cable, you need to make sure it
+ will fit the ports on your terminal and on the FreeBSD
+ system.</para>
+
+ <para>Most terminals will have DB-25 ports. Personal
+ computers, including PCs running FreeBSD, will have DB-25
+ or DB-9 ports. If you have a multiport serial card for
+ your PC, you may have RJ-12 or RJ-45 ports.</para>
+
+ <para>See the documentation that accompanied the hardware
+ for specifications on the kind of port in use. A visual
+ inspection of the port often works too.</para>
</sect4>
<sect4 id="term-portnames">
<title>Port Names</title>
- <para>In FreeBSD, you access each serial port through an entry in
- the <filename>/dev</filename> directory. There are two different
- kinds of entries:</para>
+ <para>In FreeBSD, you access each serial port through an
+ entry in the <filename>/dev</filename> directory. There
+ are two different kinds of entries:</para>
<itemizedlist>
<listitem>
<para>Call-in ports are named
<filename>/dev/ttyu<replaceable>N</replaceable></filename>
where <replaceable>N</replaceable> is the port number,
- starting from zero. Generally, you use the call-in port for
- terminals. Call-in ports require that the serial line assert
- the data carrier detect (DCD) signal to work correctly.</para>
+ starting from zero. Generally, you use the call-in
+ port for terminals. Call-in ports require that the
+ serial line assert the data carrier detect (DCD)
+ signal to work correctly.</para>
</listitem>
<listitem>
<para>Call-out ports are named
<filename>/dev/cuau<replaceable>N</replaceable></filename>.
- You usually do not use the call-out port for terminals, just
- for modems. You may use the call-out port if the serial cable
- or the terminal does not support the carrier detect
- signal.</para>
+ You usually do not use the call-out port for
+ terminals, just for modems. You may use the call-out
+ port if the serial cable or the terminal does not
+ support the carrier detect signal.</para>
</listitem>
</itemizedlist>
- <para>If you have connected a terminal to the first serial port
- (<devicename>COM1</devicename> in &ms-dos;), then you will
- use <filename>/dev/ttyu0</filename> to refer to the terminal. If
- the terminal is on the second serial port (also known as
- <devicename>COM2</devicename>), use
+ <para>If you have connected a terminal to the first serial
+ port(<devicename>COM1</devicename> in &ms-dos;), then you
+ will use <filename>/dev/ttyu0</filename> to refer to the
+ terminal. If the terminal is on the second serial port
+ (also known as <devicename>COM2</devicename>), use
<filename>/dev/ttyu1</filename>, and so forth.</para>
</sect4>
@@ -540,27 +550,28 @@
<quote>dumb</quote> multiport serial interface cards, such as
the BocaBoard 1008 and 2016, as well as more
intelligent multi-port cards such as those made by Digiboard
- and Stallion Technologies. However, the default kernel only looks
- for the standard COM ports.</para>
+ and Stallion Technologies. However, the default kernel only
+ looks for the standard COM ports.</para>
- <para>To see if your kernel recognizes any of your serial ports, watch
- for messages while the kernel is booting, or use the
- <command>/sbin/dmesg</command> command to replay the kernel's boot
- messages. In particular, look for messages that start with the
- characters <literal>uart</literal> if you use &os; 8.0 or
- higher, or <literal>sio</literal> for &os; 7.4 or older.</para>
+ <para>To see if your kernel recognizes any of your serial ports,
+ watch for messages while the kernel is booting, or use the
+ <command>/sbin/dmesg</command> command to replay the kernel's
+ boot messages. In particular, look for messages that start
+ with the characters <literal>uart</literal> if you use
+ &os; 8.0 or higher, or <literal>sio</literal> for
+ &os; 7.4 or older.</para>
<tip><para>To view just the messages that have the word
- <literal>uart</literal> or <literal>sio</literal> depending on the
- installed version of &os;, use the commands:</para>
+ <literal>uart</literal> or <literal>sio</literal> depending
+ on the installed version of &os;, use the commands:</para>
<screen>&prompt.root; <userinput>/sbin/dmesg | grep 'uart'</userinput>
&prompt.root; <userinput>/sbin/dmesg | grep 'sio'</userinput></screen>
</tip>
<para>For example, on a &os; 7.<replaceable>X</replaceable>
- system with four serial ports, these are the serial-port specific
- kernel boot messages:</para>
+ system with four serial ports, these are the serial-port
+ specific kernel boot messages:</para>
<screen>sio0 at 0x3f8-0x3ff irq 4 on isa
sio0: type 16550A
@@ -574,28 +585,28 @@ sio3: type 16550A</screen>
<para>If your kernel does not recognize all of your serial
ports, you will probably need to configure your kernel
in the <filename>/boot/device.hints</filename> file. You can
- also comment-out or completely remove lines for devices you do not
- have.</para>
+ also comment-out or completely remove lines for devices you
+ do not have.</para>
<para>Please refer to the &man.sio.4; manual page for
- more information on serial ports and multiport boards configuration.
- Be careful if you are using a configuration
+ more information on serial ports and multiport boards
+ configuration. Be careful if you are using a configuration
file that was previously used for a different version of
- FreeBSD because the device flags and the syntax have changed between
- versions.</para>
+ FreeBSD because the device flags and the syntax have changed
+ between versions.</para>
<note>
<para><literal>port IO_COM1</literal> is a substitution for
<literal>port 0x3f8</literal>, <literal>IO_COM2</literal> is
<literal>0x2f8</literal>, <literal>IO_COM3</literal> is
<literal>0x3e8</literal>, and <literal>IO_COM4</literal> is
- <literal>0x2e8</literal>, which are fairly common port addresses for
- their respective serial ports; interrupts 4, 3, 5, and 9 are fairly
- common interrupt request lines. Also note that regular serial ports
- <emphasis>cannot</emphasis> share interrupts on ISA-bus PCs
- (multiport boards have on-board electronics that allow all the
- 16550A's on the board to share one or two interrupt request
- lines).</para>
+ <literal>0x2e8</literal>, which are fairly common port
+ addresses for their respective serial ports; interrupts 4,
+ 3, 5, and 9 are fairly common interrupt request lines. Also
+ note that regular serial ports <emphasis>cannot</emphasis>
+ share interrupts on ISA-bus PCs (multiport boards have
+ on-board electronics that allow all the 16550A's on the
+ board to share one or two interrupt request lines).</para>
</note>
</sect2>
@@ -603,27 +614,29 @@ sio3: type 16550A</screen>
<sect2>
<title>Device Special Files</title>
- <para>Most devices in the kernel are accessed through <quote>device
- special files</quote>, which are located in the
- <filename>/dev</filename> directory. The <devicename>sio</devicename>
- devices are accessed through the
- <filename>/dev/ttyu<replaceable>N</replaceable></filename> (dial-in)
- and <filename>/dev/cuau<replaceable>N</replaceable></filename>
- (call-out) devices. FreeBSD also provides initialization devices
- (<filename>/dev/ttyu<replaceable>N</replaceable>.init</filename> and
+ <para>Most devices in the kernel are accessed through
+ <quote>device special files</quote>, which are located in the
+ <filename>/dev</filename> directory. The
+ <devicename>sio</devicename> devices are accessed through the
+ <filename>/dev/ttyu<replaceable>N</replaceable></filename>
+ (dial-in) and
+ <filename>/dev/cuau<replaceable>N</replaceable></filename>
+ (call-out) devices. FreeBSD also provides initialization
+ devices
+ (<filename>/dev/ttyu<replaceable>N</replaceable>.init</filename>
+ and
<filename>/dev/cuau<replaceable>N</replaceable>.init</filename>)
+ and locking devices
+ (<filename>/dev/ttyu<replaceable>N</replaceable>.lock</filename>
and
- locking devices
- (<filename>/dev/ttyu<replaceable>N</replaceable>.lock</filename> and
<filename>/dev/cuau<replaceable>N</replaceable>.lock</filename>).
- The
- initialization devices are used to initialize communications port
- parameters each time a port is opened, such as
- <literal>crtscts</literal> for modems which use
- <literal>RTS/CTS</literal> signaling for flow control. The locking
- devices are used to lock flags on ports to prevent users or programs
- changing certain parameters; see the manual pages &man.termios.4;,
- &man.sio.4;, and &man.stty.1; for
+ The initialization devices are used to initialize
+ communications port parameters each time a port is opened,
+ such as <literal>crtscts</literal> for modems which use
+ <literal>RTS/CTS</literal> signaling for flow control. The
+ locking devices are used to lock flags on ports to prevent
+ users or programs changing certain parameters; see the manual
+ pages &man.termios.4;, &man.sio.4;, and &man.stty.1; for
information on the terminal settings, locking and initializing
devices, and setting terminal options, respectively.</para>
</sect2>
@@ -632,49 +645,53 @@ sio3: type 16550A</screen>
<sect2 id="serial-hw-config">
<title>Serial Port Configuration</title>
- <indexterm><primary><devicename>ttyu</devicename></primary></indexterm>
- <indexterm><primary><devicename>cuau</devicename></primary></indexterm>
+ <indexterm><primary><devicename>ttyu</devicename></primary></indexterm>
+ <indexterm><primary><devicename>cuau</devicename></primary></indexterm>
- <para>The <devicename>ttyu<replaceable>N</replaceable></devicename> (or
- <devicename>cuau<replaceable>N</replaceable></devicename>) device is the
- regular device you will want to open for your applications. When a
- process opens the device, it will have a default set of terminal I/O
- settings. You can see these settings with the command</para>
-
- <screen>&prompt.root; <userinput>stty -a -f /dev/ttyu1</userinput></screen>
-
- <para>When you change the settings to this device, the settings are in
- effect until the device is closed. When it is reopened, it goes back to
- the default set. To make changes to the default set, you can open and
- adjust the settings of the <quote>initial state</quote> device. For
- example, to turn on <option>CLOCAL</option> mode, 8 bit communication,
- and <option>XON/XOFF</option> flow control by default for
- <devicename>ttyu5</devicename>, type:</para>
+ <para>The
+ <devicename>ttyu<replaceable>N</replaceable></devicename> (or
+ <devicename>cuau<replaceable>N</replaceable></devicename>)
+ device is the regular device you will want to open for your
+ applications. When a process opens the device, it will have a
+ default set of terminal I/O settings. You can see these
+ settings with the command</para>
+
+ <screen>&prompt.root; <userinput>stty -a -f /dev/ttyu1</userinput></screen>
+
+ <para>When you change the settings to this device, the settings
+ are in effect until the device is closed. When it is
+ reopened, it goes back to the default set. To make changes to
+ the default set, you can open and adjust the settings of the
+ <quote>initial state</quote> device. For example, to turn on
+ <option>CLOCAL</option> mode, 8 bit communication, and
+ <option>XON/XOFF</option> flow control by default for
+ <devicename>ttyu5</devicename>, type:</para>
<screen>&prompt.root; <userinput>stty -f /dev/ttyu5.init clocal cs8 ixon ixoff</userinput></screen>
- <indexterm>
- <primary>rc files</primary>
- <secondary><filename>rc.serial</filename></secondary>
- </indexterm>
-
- <para>System-wide initialization of the serial devices is
- controlled in <filename>/etc/rc.d/serial</filename>. This file
- affects the default settings of serial devices.</para>
-
- <para>To prevent certain settings from being changed by an
- application, make adjustments to the <quote>lock state</quote>
- device. For example, to lock the speed of
- <devicename>ttyu5</devicename> to 57600 bps, type:</para>
+ <indexterm>
+ <primary>rc files</primary>
+ <secondary><filename>rc.serial</filename></secondary>
+ </indexterm>
+
+ <para>System-wide initialization of the serial devices is
+ controlled in <filename>/etc/rc.d/serial</filename>. This
+ file affects the default settings of serial devices.</para>
+
+ <para>To prevent certain settings from being changed by an
+ application, make adjustments to the <quote>lock state</quote>
+ device. For example, to lock the speed of
+ <devicename>ttyu5</devicename> to 57600 bps, type:</para>
<screen>&prompt.root; <userinput>stty -f /dev/ttyu5.lock 57600</userinput></screen>
- <para>Now, an application that opens
- <devicename>ttyu5</devicename> and tries to change the speed of
- the port will be stuck with 57600 bps.</para>
-
- <para>Naturally, you should make the initial state and lock state devices
- writable only by the <username>root</username> account.</para>
+ <para>Now, an application that opens
+ <devicename>ttyu5</devicename> and tries to change the speed
+ of the port will be stuck with 57600 bps.</para>
+
+ <para>Naturally, you should make the initial state and lock
+ state devices writable only by the <username>root</username>
+ account.</para>
</sect2>
</sect1>
@@ -706,33 +723,35 @@ sio3: type 16550A</screen>
<indexterm><primary>terminals</primary></indexterm>
<para>Terminals provide a convenient and low-cost way to access
- your FreeBSD system when you are not at the computer's console or on
- a connected network. This section describes how to use terminals with
- FreeBSD.</para>
+ your FreeBSD system when you are not at the computer's console
+ or on a connected network. This section describes how to use
+ terminals with FreeBSD.</para>
<sect2 id="term-uses">
<title>Uses and Types of Terminals</title>
- <para>The original &unix; systems did not have consoles. Instead, people
- logged in and ran programs through terminals that were connected to
- the computer's serial ports. It is quite similar to using a modem and
- terminal software to dial into a remote system to do text-only
- work.</para>
-
- <para>Today's PCs have consoles capable of high quality graphics, but
- the ability to establish a login session on a serial port still exists
- in nearly every &unix; style operating system today; FreeBSD is no
- exception. By using a terminal attached to an unused serial port, you
- can log in and run any text program that you would normally run on the
- console or in an <command>xterm</command> window in the X Window
- System.</para>
-
- <para>For the business user, you can attach many terminals to a FreeBSD
- system and place them on your employees' desktops. For a home user, a
- spare computer such as an older IBM PC or a &macintosh; can be a
- terminal wired into a more powerful computer running FreeBSD. You can
- turn what might otherwise be a single-user computer into a powerful
- multiple user system.</para>
+ <para>The original &unix; systems did not have consoles.
+ Instead, people logged in and ran programs through terminals
+ that were connected to the computer's serial ports. It is
+ quite similar to using a modem and terminal software to dial
+ into a remote system to do text-only work.</para>
+
+ <para>Today's PCs have consoles capable of high quality
+ graphics, but the ability to establish a login session on a
+ serial port still exists in nearly every &unix; style
+ operating system today; FreeBSD is no exception. By using a
+ terminal attached to an unused serial port, you can log in and
+ run any text program that you would normally run on the
+ console or in an <command>xterm</command> window in the X
+ Window System.</para>
+
+ <para>For the business user, you can attach many terminals to a
+ FreeBSD system and place them on your employees' desktops.
+ For a home user, a spare computer such as an older IBM PC or a
+ &macintosh; can be a terminal wired into a more powerful
+ computer running FreeBSD. You can turn what might otherwise be
+ a single-user computer into a powerful multiple user
+ system.</para>
<para>For FreeBSD, there are three kinds of terminals:</para>
@@ -742,7 +761,8 @@ sio3: type 16550A</screen>
</listitem>
<listitem>
- <para><link linkend="term-pcs">PCs acting as terminals</link></para>
+ <para><link linkend="term-pcs">PCs acting as
+ terminals</link></para>
</listitem>
<listitem>
@@ -755,39 +775,41 @@ sio3: type 16550A</screen>
<sect3 id="term-dumb">
<title>Dumb Terminals</title>
- <para>Dumb terminals are specialized pieces of hardware that let you
- connect to computers over serial lines. They are called
- <quote>dumb</quote> because they have only enough computational power
- to display, send, and receive text. You cannot run any programs on
- them. It is the computer to which you connect them that has all the
- power to run text editors, compilers, email, games, and so
- forth.</para>
-
- <para>There are hundreds of kinds of dumb terminals made by many
- manufacturers, including Digital Equipment Corporation's VT-100 and
- Wyse's WY-75. Just about any kind will work with FreeBSD. Some
- high-end terminals can even display graphics, but only certain
- software packages can take advantage of these advanced
- features.</para>
-
- <para>Dumb terminals are popular in work environments where workers do
- not need access to graphical applications such as those provided by
- the X Window System.</para>
+ <para>Dumb terminals are specialized pieces of hardware that
+ let you connect to computers over serial lines. They are
+ called <quote>dumb</quote> because they have only enough
+ computational power to display, send, and receive text. You
+ cannot run any programs on them. It is the computer to
+ which you connect them that has all the power to run text
+ editors, compilers, email, games, and so forth.</para>
+
+ <para>There are hundreds of kinds of dumb terminals made by
+ many manufacturers, including Digital Equipment
+ Corporation's VT-100 and Wyse's WY-75. Just about any kind
+ will work with FreeBSD. Some high-end terminals can even
+ display graphics, but only certain software packages can
+ take advantage of these advanced features.</para>
+
+ <para>Dumb terminals are popular in work environments where
+ workers do not need access to graphical applications such as
+ those provided by the X Window System.</para>
</sect3>
<sect3 id="term-pcs">
<title>PCs Acting as Terminals</title>
- <para>If a <link linkend="term-dumb">dumb terminal</link> has just
- enough ability to display, send, and receive text, then certainly
- any spare personal computer can be a dumb terminal. All you need is
- the proper cable and some <emphasis>terminal emulation</emphasis>
- software to run on the computer.</para>
-
- <para>Such a configuration is popular in homes. For example, if your
- spouse is busy working on your FreeBSD system's console, you can do
- some text-only work at the same time from a less powerful personal
- computer hooked up as a terminal to the FreeBSD system.</para>
+ <para>If a <link linkend="term-dumb">dumb terminal</link> has
+ just enough ability to display, send, and receive text, then
+ certainly any spare personal computer can be a dumb
+ terminal. All you need is the proper cable and some
+ <emphasis>terminal emulation</emphasis> software to run on
+ the computer.</para>
+
+ <para>Such a configuration is popular in homes. For example,
+ if your spouse is busy working on your FreeBSD system's
+ console, you can do some text-only work at the same time
+ from a less powerful personal computer hooked up as a
+ terminal to the FreeBSD system.</para>
<para>There are at least two utilities in the base-system of
&os; that can be used to work through a serial connection:
@@ -807,19 +829,19 @@ sio3: type 16550A</screen>
port number.</para>
<note>
- <para>Note that device numbers in &os; start from zero and not
- one (like they do, for instance in &ms-dos;-derived systems).
- This means that what &ms-dos;-based systems call
- <devicename>COM1</devicename> is usually
+ <para>Note that device numbers in &os; start from zero and
+ not one (like they do, for instance in &ms-dos;-derived
+ systems). This means that what &ms-dos;-based systems
+ call <devicename>COM1</devicename> is usually
<filename>/dev/cuau0</filename> in &os;.</para>
</note>
<note>
<para>Some people prefer to use other programs, available
- through the Ports Collection. The Ports include quite a few
- utilities which can work in ways similar to &man.cu.1; and
- &man.tip.1;,
- i.e., <filename role="package">comms/minicom</filename>.</para>
+ through the Ports Collection. The Ports include quite a
+ few utilities which can work in ways similar to &man.cu.1;
+ and &man.tip.1;, i.e., <filename
+ role="package">comms/minicom</filename>.</para>
</note>
</sect3>
@@ -827,23 +849,26 @@ sio3: type 16550A</screen>
<title>X Terminals</title>
<para>X terminals are the most sophisticated kind of terminal
- available. Instead of connecting to a serial port, they usually
- connect to a network like Ethernet. Instead of being relegated to
- text-only applications, they can display any X application.</para>
-
- <para>We introduce X terminals just for the sake of completeness.
- However, this chapter does <emphasis>not</emphasis> cover setup,
- configuration, or use of X terminals.</para>
+ available. Instead of connecting to a serial port, they
+ usually connect to a network like Ethernet. Instead of
+ being relegated to text-only applications, they can display
+ any X application.</para>
+
+ <para>We introduce X terminals just for the sake of
+ completeness. However, this chapter does
+ <emphasis>not</emphasis> cover setup, configuration, or use
+ of X terminals.</para>
</sect3>
</sect2>
<sect2 id="term-config">
<title>Configuration</title>
- <para>This section describes what you need to configure on your FreeBSD
- system to enable a login session on a terminal. It assumes you have
- already configured your kernel to support the serial port to which the
- terminal is connected—and that you have connected it.</para>
+ <para>This section describes what you need to configure on your
+ FreeBSD system to enable a login session on a terminal. It
+ assumes you have already configured your kernel to support the
+ serial port to which the terminal is connected—and that
+ you have connected it.</para>
<para>Recall from <xref linkend="boot"/> that the
<command>init</command> process is responsible for all process
@@ -856,18 +881,19 @@ sio3: type 16550A</screen>
program.</para>
<para>Thus, to configure terminals for your FreeBSD system the
- following steps should be taken as <username>root</username>:</para>
+ following steps should be taken as
+ <username>root</username>:</para>
<procedure>
<step>
- <para>Add a line to <filename>/etc/ttys</filename> for the entry in
- the <filename>/dev</filename> directory for the serial port if it
- is not already there.</para>
+ <para>Add a line to <filename>/etc/ttys</filename> for the
+ entry in the <filename>/dev</filename> directory for the
+ serial port if it is not already there.</para>
</step>
<step>
- <para>Specify that <command>/usr/libexec/getty</command> be run on
- the port, and specify the appropriate
+ <para>Specify that <command>/usr/libexec/getty</command>
+ be run on the port, and specify the appropriate
<replaceable>getty</replaceable> type from the
<filename>/etc/gettytab</filename> file.</para>
</step>
@@ -892,31 +918,34 @@ sio3: type 16550A</screen>
</procedure>
<para>As an optional step, you may wish to create a custom
- <replaceable>getty</replaceable> type for use in step 2 by making an
- entry in <filename>/etc/gettytab</filename>. This chapter does
- not explain how to do so; you are encouraged to see the
- &man.gettytab.5; and the &man.getty.8; manual pages for more
- information.</para>
+ <replaceable>getty</replaceable> type for use in step 2 by
+ making an entry in <filename>/etc/gettytab</filename>. This
+ chapter does not explain how to do so; you are encouraged to
+ see the &man.gettytab.5; and the &man.getty.8; manual pages
+ for more information.</para>
<sect3 id="term-etcttys">
- <title>Adding an Entry to <filename>/etc/ttys</filename></title>
+ <title>Adding an Entry to
+ <filename>/etc/ttys</filename></title>
- <para>The <filename>/etc/ttys</filename> file lists all of the ports
- on your FreeBSD system where you want to allow logins. For example,
- the first virtual console <devicename>ttyv0</devicename> has an entry
- in this file. You can log in on the console using this entry. This
- file also contains entries for the other virtual consoles, serial
- ports, and pseudo-ttys. For a hardwired terminal, just list the
- serial port's <filename>/dev</filename> entry without the
- <filename>/dev</filename> part (for example,
+ <para>The <filename>/etc/ttys</filename> file lists all of the
+ ports on your FreeBSD system where you want to allow logins.
+ For example, the first virtual console
+ <devicename>ttyv0</devicename> has an entry in this file.
+ You can log in on the console using this entry. This
+ file also contains entries for the other virtual consoles,
+ serial ports, and pseudo-ttys. For a hardwired terminal,
+ just list the serial port's <filename>/dev</filename> entry
+ without the <filename>/dev</filename> part (for example,
<filename>/dev/ttyv0</filename> would be listed as
<devicename>ttyv0</devicename>).</para>
<para>A default FreeBSD install includes an
- <filename>/etc/ttys</filename> file with support for the first
- four serial ports: <devicename>ttyu0</devicename> through
- <devicename>ttyu3</devicename>. If you are attaching a terminal
- to one of those ports, you do not need to add another entry.</para>
+ <filename>/etc/ttys</filename> file with support for the
+ first four serial ports: <devicename>ttyu0</devicename>
+ through <devicename>ttyu3</devicename>. If you are
+ attaching a terminal to one of those ports, you do not need
+ to add another entry.</para>
<example id="ex-etc-ttys">
<title>Adding Terminal Entries to
@@ -937,14 +966,13 @@ sio3: type 16550A</screen>
id="co-ttys-line1col3"/> on<co
id="co-ttys-line1col4"/> insecure<co
id="co-ttys-line1col5"/>
-ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure
- </programlisting>
+ttyu5 "/usr/libexec/getty std.19200" vt100 on insecure</programlisting>
<calloutlist>
<callout arearefs="co-ttys-line1col1">
<para>The first field normally specifies the name of
- the terminal special file as it is found in
- <filename>/dev</filename>.</para>
+ the terminal special file as it is found in
+ <filename>/dev</filename>.</para>
</callout>
<callout arearefs="co-ttys-line1col2">
@@ -959,18 +987,18 @@ ttyu5 "/usr/libexec/getty std.19200"
<replaceable>getty</replaceable> type. A
<replaceable>getty</replaceable> type configures
characteristics on the terminal line, like bps rate
- and parity. The <command>getty</command> program reads
- these characteristics from the file
+ and parity. The <command>getty</command> program
+ reads these characteristics from the file
<filename>/etc/gettytab</filename>.</para>
<para>The file <filename>/etc/gettytab</filename>
contains lots of entries for terminal lines both old
and new. In almost all cases, the entries that start
with the text <literal>std</literal> will work for
- hardwired terminals. These entries ignore parity.
+ hardwired terminals. These entries ignore parity.
There is a <literal>std</literal> entry for each bps
rate from 110 to 115200. Of course, you can add your
- own entries to this file. The &man.gettytab.5; manual
+ own entries to this file. The &man.gettytab.5; manual
page provides more information.</para>
<para>When setting the <replaceable>getty</replaceable>
@@ -979,8 +1007,8 @@ ttyu5 "/usr/libexec/getty std.19200"
match.</para>
<para>For our example, the Wyse-50 uses no parity and
- connects at 38400 bps. The 286 PC uses no parity
- and connects at 19200 bps.</para>
+ connects at 38400 bps. The 286 PC uses no
+ parity and connects at 19200 bps.</para>
</callout>
<callout arearefs="co-ttys-line1col3">
@@ -1038,13 +1066,15 @@ ttyu5 "/usr/libexec/getty std.19200"
<para>After making the necessary changes to the
<filename>/etc/ttys</filename> file you should send a SIGHUP
(hangup) signal to the <command>init</command> process to
- force it to re-read its configuration file. For example:</para>
+ force it to re-read its configuration file. For
+ example:</para>
<screen>&prompt.root; <userinput>kill -HUP 1</userinput></screen>
<note>
- <para><command>init</command> is always the first process run
- on a system, therefore it will always have PID 1.</para>
+ <para><command>init</command> is always the first process
+ run on a system, therefore it will always have PID
+ 1.</para>
</note>
<para>If everything is set up correctly, all cables are in
@@ -1058,31 +1088,31 @@ ttyu5 "/usr/libexec/getty std.19200"
<sect2 id="term-debug">
<title>Troubleshooting Your Connection</title>
- <para>Even with the most meticulous attention to detail, something could
- still go wrong while setting up a terminal. Here is a list of
- symptoms and some suggested fixes.</para>
+ <para>Even with the most meticulous attention to detail,
+ something could still go wrong while setting up a terminal.
+ Here is a list of symptoms and some suggested fixes.</para>
<sect3>
<title>No Login Prompt Appears</title>
- <para>Make sure the terminal is plugged in and powered up. If it
- is a personal computer acting as a terminal, make sure it is
- running terminal emulation software on the correct serial
+ <para>Make sure the terminal is plugged in and powered up. If
+ it is a personal computer acting as a terminal, make sure it
+ is running terminal emulation software on the correct serial
port.</para>
- <para>Make sure the cable is connected firmly to both the terminal
- and the FreeBSD computer. Make sure it is the right kind of
- cable.</para>
-
- <para>Make sure the terminal and FreeBSD agree on the bps rate and
- parity settings. If you have a video display terminal, make
- sure the contrast and brightness controls are turned up. If it
- is a printing terminal, make sure paper and ink are in good
- supply.</para>
-
- <para>Make sure that a <command>getty</command> process is running
- and serving the terminal. For example, to get a list of
- running <command>getty</command> processes with
+ <para>Make sure the cable is connected firmly to both the
+ terminal and the FreeBSD computer. Make sure it is the
+ right kind of cable.</para>
+
+ <para>Make sure the terminal and FreeBSD agree on the bps rate
+ and parity settings. If you have a video display terminal,
+ make sure the contrast and brightness controls are turned
+ up. If it is a printing terminal, make sure paper and ink
+ are in good supply.</para>
+
+ <para>Make sure that a <command>getty</command> process is
+ running and serving the terminal. For example, to get a
+ list of running <command>getty</command> processes with
<command>ps</command>, type:</para>
<screen>&prompt.root; <userinput>ps -axww|grep getty</userinput></screen>
@@ -1096,24 +1126,25 @@ ttyu5 "/usr/libexec/getty std.19200"
<screen>22189 d1 Is+ 0:00.03 /usr/libexec/getty std.38400 ttyu1</screen>
- <para>If no <command>getty</command> process is running, make sure
- you have enabled the port in <filename>/etc/ttys</filename>.
- Also remember to run <command>kill -HUP 1</command>
- after modifying the <filename>ttys</filename> file.</para>
+ <para>If no <command>getty</command> process is running, make
+ sure you have enabled the port in
+ <filename>/etc/ttys</filename>. Also remember to run
+ <command>kill -HUP 1</command> after modifying the
+ <filename>ttys</filename> file.</para>
<para>If the <command>getty</command> process is running
but the terminal still does not display a login prompt,
or if it displays a prompt but will not allow you to
type, your terminal or cable may not support hardware
- handshaking. Try changing the entry in
+ handshaking. Try changing the entry in
<filename>/etc/ttys</filename> from
<literal>std.38400</literal> to
<literal>3wire.38400</literal> (remember to run
<command>kill -HUP 1</command> after modifying
- <filename>/etc/ttys</filename>). The
+ <filename>/etc/ttys</filename>). The
<literal>3wire</literal> entry is similar to
<literal>std</literal>, but ignores hardware
- handshaking. You may need to reduce the baud rate or
+ handshaking. You may need to reduce the baud rate or
enable software flow control when using
<literal>3wire</literal> to prevent buffer
overflows.</para>
@@ -1123,12 +1154,12 @@ ttyu5 "/usr/libexec/getty std.19200"
<sect3>
<title>If Garbage Appears Instead of a Login Prompt</title>
- <para>Make sure the terminal and FreeBSD agree on the bps rate and
- parity settings. Check the <command>getty</command> processes
- to make sure the
- correct <replaceable>getty</replaceable> type is in use. If
- not, edit <filename>/etc/ttys</filename> and run <command>kill
- -HUP 1</command>.</para>
+ <para>Make sure the terminal and FreeBSD agree on the bps rate
+ and parity settings. Check the <command>getty</command>
+ processes to make sure the correct
+ <replaceable>getty</replaceable> type is in use. If not,
+ edit <filename>/etc/ttys</filename> and run <command>kill
+ -HUP 1</command>.</para>
</sect3>
@@ -1137,8 +1168,8 @@ ttyu5 "/usr/libexec/getty std.19200"
Typed</title>
<para>Switch the terminal (or the terminal emulation software)
- from <quote>half duplex</quote> or <quote>local echo</quote> to
- <quote>full duplex.</quote></para>
+ from <quote>half duplex</quote> or <quote>local echo</quote>
+ to <quote>full duplex.</quote></para>
</sect3>
</sect2>
@@ -1181,24 +1212,26 @@ ttyu5 "/usr/libexec/getty std.19200"
similar to connecting terminals except that you are dealing with
modems instead of terminals.</para>
- <sect2>
- <title>External Versus Internal Modems</title>
+ <sect2>
+ <title>External Versus Internal Modems</title>
- <para>External modems seem to be more convenient for dial-up, because
- external modems often can be semi-permanently configured via
- parameters stored in non-volatile RAM and they usually provide
- lighted indicators that display the state of important RS-232
- signals. Blinking lights impress visitors, but lights are also very
- useful to see whether a modem is operating properly.</para>
-
- <para>Internal modems usually lack non-volatile RAM, so their
- configuration may be limited only to setting DIP switches. If your
- internal modem has any signal indicator lights, it is probably
- difficult to view the lights when the system's cover is in
- place.</para>
+ <para>External modems seem to be more convenient for dial-up,
+ because external modems often can be semi-permanently
+ configured via parameters stored in non-volatile RAM and they
+ usually provide lighted indicators that display the state of
+ important RS-232 signals. Blinking lights impress visitors,
+ but lights are also very useful to see whether a modem is
+ operating properly.</para>
+
+ <para>Internal modems usually lack non-volatile RAM, so their
+ configuration may be limited only to setting DIP switches.
+ If your internal modem has any signal indicator lights, it is
+ probably difficult to view the lights when the system's cover
+ is in place.</para>
<sect3>
*** DIFF OUTPUT TRUNCATED AT 1000 LINES ***
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