Modem won't connect at full speed

[Don Lewis]

On 19 Aug, Lars Eighner wrote:
> This has been answered by somebody on some forum, but I lost it.
> 
> I have an internal hardware modem.  I have configured ppp on demand.
> Unfortunately, my 56k modem connects at an effective rate of about
> 14.4k when I use ppp under FreeBSD.  I have got normal connect speeds
> with the same modem and the same ISP using Linux in the past.
> 
> Here is my ppp.log.  Notice the CCP rejection line, which I
> guess is pertinent:
> 
> Aug 19 20:02:59 pearl ppp[190]: tun0: Phase: bundle: Establish
> Aug 19 20:02:59 pearl ppp[190]: tun0: Phase: deflink: closed -> opening
> Aug 19 20:02:59 pearl ppp[190]: tun0: Phase: deflink: Connected!
> Aug 19 20:02:59 pearl ppp[190]: tun0: Phase: deflink: opening -> dial
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: Phone: 4857440
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: deflink: Dial attempt 1 of 1
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: Send: ATZ^M
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: Expect(5): OK
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: Received: ATDT4857440^MATZ^M^M
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: Received: OK
> Aug 19 20:02:59 pearl ppp[190]: tun0: Chat: Send: ATDT4857440^M
> Aug 19 20:03:01 pearl ppp[190]: tun0: Chat: Expect(40): CONNECT
> Aug 19 20:03:01 pearl ppp[190]: tun0: Chat: Received: ^M
> Aug 19 20:03:18 pearl ppp[190]: tun0: Chat: Received: ATDT4857440^M^M
> Aug 19 20:03:18 pearl ppp[190]: tun0: Chat: Received: CONNECT

If you manually dial using cu or tip, what connection speed does the
modem report?


> Here are my modem hardware setting (with explanations in square
> brackets):

> 
>    BAUD=9600  PARITY=N  WORDLEN=8
>    DIAL=TONE    ON HOOK   CID=0
> 
>    &A3  &B1  &C1  &D2  &G0  &H1  &I0  &K1
> [&An   n=0  Disable /ARQ Result Codes
>        n=1  Enable /ARQ Result Codes
>        n=2  Enable /Modulation Codes
>       *n=3  Enable /Extra Result Codes
>  &Bn   n=0  Floating DTE Speed
>       *n=1  Fixed DTE Speed
>        n=2  DTE Speed Fixed When ARQ

It is somewhat worrysome that your modem is reporting 9600 BAUD in the
fixed DTE speed setting.  I don't know about USR Internal modems, but at
least some implementations will pace the data flow rate to the reported
DTE speed to avoid overwhelming the host with quick bursts of
interrupts.  This might be the reason for your slow connection speeds.

It's been a while since I've used the proper incantation to reset the
speed on a USR modem, but I think with a serial modem, the procedure was
to connect to the modem, repeatedly type AT to get its attention, put it
in variable speed mode, reconnect at the desired speed, and set &B1 to
get it back to fixed rate.  Probably something similar will work with an
internal modem.  The modem will probably peek at the UART speed control
register to pick up the desired DTE rate and save it to its non-volatile
memory.