LinuxQuestions.org - Not receiving data from serial modem.

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Not receiving data from serial modem.

I have an external 56k swann speed demon connected to ttyS1. When I open minicom, the modem initialises (and the appropriate lights flash on the modem), but nothing will happen from there. It won't even echo back what I type in, even if I wait for ages. Similarly, when I attempt to dialup using KPPP it just sits there "Expecting: OK".

I am using a fresh installation of Mandrake 9.1. The modem worked without hassles on Mandrake 9.0.

Code:

# setserial /dev/ttyS1

/dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3

...which matches my BIOS settings.

Some things while KPPP is trying to connect:

Code:

# lsof /dev/ttyS*

COMMAND  PID USER  FD  TYPE DEVICE SIZE NODE NAME

X      1527 root  7u  CHR  4,64      414 /dev/tts/0

kppp    2908  joe  11u  CHR  4,65      417 /dev/tts/1

kppp    2909 root  3u  CHR  4,65      417 /dev/tts/1



# cat /proc/interrupts

...

  3:      22      XT-PIC  serial

...



# statserial

Signal  Pin  Pin  Direction  Status  Full

Name    (25) (9)  (computer)        Name

-----  ---  ---  ---------  ------  -----

FG      1    -      -          -  Frame Ground

TxD      2    3      out        -  Transmit Data

RxD      3    2      in          -  Receive Data

RTS      4    7      out        1  Request To Send

CTS      5    8      in          0  Clear To Send

DSR      6    6      in          0  Data Set Ready

GND      7    5      -          -  Signal Ground

DCD      8    1      in          0  Data Carrier Detect

DTR    20    4      out        1  Data Terminal Ready

RI      22    9      in          0  Ring Indicator

Any help greatly appreciated. :D

Check your /var/log/syslog to see if there are any errors there. Perhaps you need to configure nameserver in etc/ppp/resolv.conf

Nothing relevant in syslog. I wouldn't think it has to do with nameserver setup, but more with the configuration of the serial port.

You could try running, dmesg with your modem switched on,it just might give you a different location than what you have set up in setseial.

Lachlan

What message are you getting when you are in kppp setup and you do query modem?

It seems to query the modem properly, but all the messages are just empty. With everything I do, it's as though data can be sent to the modem, but none is ever received.

Quote:

Originally posted by lachlan
You could try running, dmesg with your modem switched on,it just might give you a different location than what you have set up in setseial.

Lachlan

Can't find anything except what setserial says.

Hi all,
I'm having the same problem with my internal modem while using KPPP.
The "Initializing modem..." is displayed and Login Script Debug Window shows nothing while Expecting: ok is displayed at the botton.

Any help is appriciated.
Azad

Same Issue withe Fedora Core 6 Help

I have a USR5686 E Serial modem located on ttyS0 this is not a win modem. KPPP will not detect the modem unless i create a soft link to /dev/modem. Once the link is created I can query my modem but nothing is returned. when i try to dial out the software says initializing modem and the log states waiting for OK.

I have run set serial command: setserial /dev/modem or setserial /dev/ttyS0 and setserial returns : Cannot get serial info:Invalid Argument

I have a A8V Asus Motherboard in the BIOS my serial port is assigned address 2E8/IRQ4.

The kernel version of Linux that I am using is 2.6.18-1.2798fc6xen Fedora Core 6

PPP Version ppp-2.4.4-1.fc6.i386.rpm

Also could you please include the file that i need to amend so that my /dev/modem soft link does not have to be recreated every time I reboot.

Any help would be greatly appreciated.

Be aware of hardware signals being received by the serial modem.

The Linux host must see DSR and CTS from the serial device.

The Linux host will raise DTR and RTS when the tty is opened by a process.

DSR tells the Linux host that the modem is in a Data Set Ready state ...

Make sure that the cable is good.

The typical AT command to enable echo is ATE1.

Help I am not sure what you mean or how to check it sorry I am a big time Linux newbie.

All I know is the cable is working because I am using the modem from winxp atm

You can check serial statistics through the /proc filesystem:

Code:

n600c ~ # cat /proc/tty/driver/serial

serinfo:1.0 driver revision:

0: uart:16550A port:000003F8 irq:4 tx:0 rx:0 RTS|DTR

When I tried that command it said no such directory so I navigated my way as far as I could in the file system and made it to /proc/tty/driver/ in the driver directory there was one file rfcomm I opened it with emacs its empty. also in /proc/tty/ there is a file drivers and ldisc both are empty as well.

Ok, it appears your kernel doesn't have the support...

What LED's are indicated on the modem ... when you open the TTY device ?

The only light that stays on is the CS led. Although it seems every time I Try and dial out or Query my modem from KPPP when i return to windows I have to reboot the modem to dial outfrom windows.