having trouble receiving serial data using my USB->serial adaptor

[Rohit Grover]

Hi,

I am having trouble getting my BAFO 810 USB->serial adaptor to
work. I have built the uplcom and ucom drivers into the kernel,
and my USB->serial adaptor is recognized at boot, as can be
inferred from the following lines from /var/run/dmesg.boot:

ucom0: <Prolific Technology Inc. USB-Serial Controller, class
0/0, rev 1.10/3.\ 00, addr 2> on uhub3

I am using minicom to drive /dev/cuaU0 at 115200 8N1.

If I connect the Tx and Rx lines (pins 2 and 3) of the DB9
connector, I can get echoes of my keystrokes on the minicom
terminal.

Unfortunately, I am unable to connect to an embedded device which
supports serial connections at 115200 8N1. When I plug the serial
output connector of my adaptor to a NULL modem and then to the
target embedded system, I don't see any serial output from the
device on my minicom terminal. This same device communicates
correctly with the serial port of my linux desktop with minicom
and 115200 8N1.

As a further experiment, I manually connected pins 2,3, and 5 of
the serial end of my adaptor to pins 3,2, and 5 respectively of
the embedded device, but still no luck.

What am I missing?

regards,