Talk to modem with USB to serial adapter: fail

From	Mike Spencer <mds@bogus.nodomain.nowhere>
Newsgroups	comp.os.linux.hardware
Subject	Talk to modem with USB to serial adapter: fail
Date	2015-08-12 03:03 -0300
Organization	Bridgewater Institute for Advanced Study - Blacksmith Shop
Message-ID	<87lhdhqc05.fsf@bogus.nodomain.nowhere> (permalink)

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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

The system seems to see it as /dev/ttyUSB0. "echo at > /dev/ttyUSB0"
exits with no error but no lights blink on the modem.

cat /proc.tty/usbserial replies:

    usbserinfo:1.0 driver:2.0
    0: module:ftdi_sio name:"FTDI USB Serial Device" 
    vendor:0403 product:6001 num_ports:1 port:0 path:usb-0000:00:10.0-2

and lsmod |grep serial shows:

    usbserial              19969  3 ftdi_sio

Using the scripts that work fine from a desktop with a standard serial
port, pppd appears to exit 0 without doing anything.

In the past, I've used minicom to test modem connections. But, after
telling minicom to talk to /dev/ttyUSB0, minicom echoes non-ASCII
chars in response to lower case (a=degree-symbol, t=phi or maybe
slashed 0) and doesn't respond at all to upper case.  In any case,
nothing seems to get to the modem.

Same thing happens in an xterm or in a console. /dev/ttyUSB0 is
rw-rw-rw, pppd is suid.  Excepting the substitution of ttyUSB0for
ttyS0, details are the same as on the working desktop system.

Running Slackware 14.1 but with a 3.16.1 kernel.

Has anybody dealt with this, have a tidy solution?

Yes, I have some things to verify, such as the RS232 plug sex
adapter. Just hoping there's a wizard out there with a fix.

Tnx,

-- 
Mike Spencer                  Nova Scotia, Canada

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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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