SUMMARY: Capturing text from a serial port

From: John Clinton (
Date: Wed Dec 02 1998 - 06:16:06 CST

Thanks to all who responded. Apologies for my delay posting the Summary.

The question was: How do I capture text from a serial port and log to a

There were two general responses

Option one: Use Kermit

Option two: Write a shell script using stty. Douglas Carr had the cleanest approach I think. His email and
script is below. Please contact him for permission to use it.


  Several years ago my boss asked me to do something
similar. We have a in house digital phone system in our
department. This system has the capabilities of outputting
phone usage data via a serial port. Not wanting to do a
lot of C programming I decided to write a small shell
program to capture ASCII data arriving on the serial port
to a file. It was quite a simple program once I did
some research. Your free to use it if you want.

****** Cut Here ******

# Phone * Watch
# 02/02/98
# Douglas E. Carr
# All rights assigned to,
# Agricultural Engineering Department
# University of Kentucky
# A program to monitor the data comming in on "/dev/ttyb" from
# the Executech II phone system.
# Features that need to be added in the future.
# 1. File (device locking).
# 2. Copy and move the data file to the administrators login.

# Create a new file each month, with the format "mmyy.log"

#FILE=/var/log/`date +%m%y.log`

# Assign file descriptor 3 to "/dev/ttyb"

exec 3< /dev/ttyb

# Set IOCTL parameters for "/dev/ttyb"

/usr/5bin/stty 2400 -parenb -parodd cs7 cstopb -ixoff igncr < /dev/ttyb

# Capture date from "/dev/ttyb" forever(?).

while true
  cat <&3 >> $FILE

******* Cut here *******

-----Original Message-----
[]On Behalf Of John
Sent: Wednesday, November 25, 1998 8:20 AM
To: Sun Managers
Subject: Capturing text from a serial port

Hi Sun Managers,

I need to capture the text sent to a Sun's serial port and send it to a

Background information:

There is PC sending text out its serial port intended for a printer (just
plain text). My manager has asked that I connect this PC's serial port to a
Sun (Solaris 2.6) and send this text to a file.

How do I configure the port for this on the Sun? I plan on using a null
modem cable and make sure all the pin outs are correct, however I need
direction with the software configuration.

Can anyone point me in the right direction? I have searched on the web
and only found general serial port configuration guidelines.

John Clinton

Other responses included using PEEK

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