Re: Talk to modem with USB to serial adapter: fail

From	Mike Spencer <mds@bogus.nodomain.nowhere>
Newsgroups	comp.os.linux.hardware
Subject	Re: Talk to modem with USB to serial adapter: fail
Date	2015-08-13 04:19 -0300
Organization	Bridgewater Institute for Advanced Study - Blacksmith Shop
Message-ID	<8737zn3bb5.fsf@bogus.nodomain.nowhere> (permalink)
References	<87lhdhqc05.fsf@bogus.nodomain.nowhere> <mqgaos$31j$1@dont-email.me>

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Jerry Peters <jerry@example.invalid> writes:

> Mike Spencer <mds@bogus.nodomain.nowhere> wrote:
>
>> I want to use a USR 56K serial modem with a late-model Acer laptop (no
>> serial port).  Nothing seems to reaching the modem.
>> 
>> lsusb see the adapter as:
>> 
>>  Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
>>  USB ID 0403:6001
>
> I used to use a serial adapter to a modem when I'd visit my parents in
> Florida, never had any problems, it all just worked. I don't remember
> which serial adapters I used (I had 2 different ones) but it wasn't an
> fdti. Before spending too much time I'd suggest trying a different
> serial adapter. Just a thought, does the fdti need firmware? modinfo
> should show if it does.

I should have had a clue. Kind persons from another group reminded me
that I shoud use stty on /dev/ttyUSB0 and sure enough, the adapter
defaults to 9600. Reset that to 115200 with stty and minicom(1) works
as expected.

So the hardware -- USB/serial adapter, cable, sex change plug and
modem all work.

But chat(8) invoked by pppd from dialer script fails.  It appears
that, using chat, no replies are getting back to chat and the modem
isn't responding to AT-commands sent.  Using two shells, one to echo
"AT" to /dev/ttyUSB0 and one to cat /dev/ttyUSB0, the only thing that
comes back from the cat is "AT". So minicom is doing *something* right
that neither chat(8) nor echo/cat are doing.

Probably not a hardware problem any more but any advice welcome
nevertheless.  I'm still stuck, just not head-down. :-)

Tnx,
-- 
Mike Spencer                  Nova Scotia, Canada

Thread

Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-12 03:03 -0300
  Re: Talk to modem with USB to serial adapter: fail Jerry Peters <jerry@example.invalid> - 2015-08-12 20:36 +0000
    Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-13 04:19 -0300
      Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-13 21:17 +0000
        Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-15 02:26 -0300
          Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-16 00:45 +0000
            Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-16 00:43 -0300
              Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-16 20:09 +0000
            Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-16 01:41 -0300
              Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-16 20:10 +0000
                Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-16 22:28 -0300
                Re: Talk to modem with USB to serial adapter: fail Michael Black <et472@ncf.ca> - 2015-08-16 22:48 -0400
                Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-17 03:35 -0300
                Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-17 03:22 -0300
                Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-17 23:50 +0000
                Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-18 16:16 -0300
                Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-21 03:31 +0000
                Re: Talk to modem with USB to serial adapter: fail Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-08-25 01:58 -0300
                Re: Talk to modem with USB to serial adapter: fail Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-08-27 02:28 +0000
                All better now (Re: Talk to modem with USB to serial adapter: fail) Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-09-03 18:53 -0300
                Re: All better now (Re: Talk to modem with USB to serial adapter: fail) Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-09-04 20:00 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter: fail) Richard Kettlewell <rjk@greenend.org.uk> - 2015-09-04 21:09 +0100
                Re: All better now (Re: Talk to modem with USB to serial adapter: fail) Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-09-04 23:14 -0300
                Re: All better now (Re: Talk to modem with USB to serial adapter: fail) Richard Kettlewell <rjk@greenend.org.uk> - 2015-09-05 10:08 +0100
                Re: All better now (Re: Talk to modem with USB to serial adapter: fail) Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-09-05 18:08 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:  fail) Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-09-06 01:31 -0300
                Re: All better now (Re: Talk to modem with USB to serial adapter:  fail) Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-09-06 19:17 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:   fail) Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-09-17 01:26 -0300
                Re: All better now (Re: Talk to modem with USB to serial adapter:   fail) Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-09-17 05:53 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:    fail) Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-09-17 04:02 -0300
                Re: All better now (Re: Talk to modem with USB to serial adapter:    fail) Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-09-17 18:02 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:     fail) Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-09-18 02:05 -0300
                Re: All better now (Re: Talk to modem with USB to serial adapter:    fail) Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-09-17 19:14 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:    fail) Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-09-18 01:55 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:    fail) Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-09-18 21:22 +0000
                Re: All better now (Re: Talk to modem with USB to serial adapter:   fail) Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2015-09-17 19:12 +0000

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