Hi Cory.

I note the "-clocal" which is telling stty to honor the
modem control signals, and I'm not sure what state "raw"
leaves the "crtscts" and "cdsrdsr" options in.
It couldn't be something as silly as CTS/RTS, DSR/DTR flow
control doing its thing could it?

Without knowing what signals are in use on the interface,
I can't guess what may or may not be critical.

The signals may be jumpered into a fixed state, required,
or not even present.

An RS232 tester could also prove useful in dignosing the issue.

(The ones with the dual colour LEDs for the the various pins.

They are not as common as they used to be, but they should
still be a part of the toolbox for anyone that needs to deal
with older RS232 technologies. Amazon show a couple of options
including one that is a USB to Serial adapter with built-in LEDs,
but that one doesn't have the two colour LEDs, so only tells
half the story.)

Morrie.

From: luv-main [mailto:luv-main-bounces@luv.asn.au] On Behalf Of cory seligman via luv-main
Sent: Monday, 20 August 2018 10:30 AM
To: luv-main
Subject: expect script

Hi All,

I'm having some trouble making expect work.

I need it to talk to some vintage equipment over usb serial, and I think I'm getting hung up on opening the port.

When the script runs, it just connects to the device and sits there. I can drive it interactively, but it doesn't attempt to automate anything.

Any ideas? Thanks.

My expect script looks like this:

#!/usr/bin/expect -f

# device
set modem /dev/ttyUSB0

# keep it open
exec sh -c "sleep 3 < $modem" &

# serial port parameters
exec stty -F $modem 2400 raw -clocal -echo -istrip -hup

# connect
send_user "connecting to $modem, exit with ~,\n"
spawn -open [open $modem w+]
interact {
    ~, exit
    ~~ {send "\034"}
}

set force_conservative 1 ;# set to 1 to force conservative mode even if
              ;# script wasn't run conservatively originally
if {$force_conservative} {
    set send_slow {1 .1}
    proc send {ignore arg} {
        sleep .1
        exp_send -s -- $arg
    }
}

set timeout -1
match_max 100000
send -- "\r"
send -- "\r"
expect  ">"
send -- "p 7d91\r"
expect  ">"
send -- "p b2ff\r"
expect  ">"
send -- "h\r"
expect  ">"
send -- "td\r"
expect "td\r
  18 215  12  24  33\r
>"
send -- "gd 215\r"
expect eof