Modem connection

[Rex Tran]

I have a USR 56K modem attached to the GSP modem port and at times answers but can not get a login prompt.
I have to get in the server by other means. Dial in PCAnywhere and telnet to the server just to do a "cu" command. When attaching to the modem I see what seems like modem noise. It pauses and I just type in "AT" and responds back with OK.
All is good for about 2-4 hours.
I have tried the obvious, is the modem/cable near or on a UPS or other "noisy" power hardware.
Is there an explanation for this noise? And can it be aliminated?

System Hardware Info
Model: 9000/800/L3000-7x
/etc/inittab:
a0:234:respawn:/usr/sbin/getty -h ttyd0p2 192
/etc/gettydefs:
192 # B19200 SANE CS8 ISTRIP IXANY TAB3 HUPCL
# B19200 SANE CS8 ISTRIP IXANY TAB3 HUPCL
#Modem Login: #192
/etc/uucp/Devices:
ACU cul0p2 - 19200 hayes
Direct cul0p2 - 19200 direct
I have attached a screenshot.
Thanks
--rex

[Ron Kinner]

Go into your modem and tell it:
ATI4

That should cause it to display its current configuration. Capture that and post it back to us.

Ron

[Rex Tran]

heres the requested ati4 info.

[Vijeesh CTK]

Hi,

Just feed the below setting to the modem and try


AT&FE0Q1S0=1&C0&D0\J0\N3\Q3&W


Modem Command Function
AT Attention code. Must be first in line
&F Resets modem to factory default settings
E0 Modem doesn't echo commands back to host
Q1 Modem doesn't display result codes
S0=1 Modem answers after 1 ring
&C0 Carrier Detect signal always on
&D0 Ignore DTR signal from mainframe
\J0 Disable serial baud rate adjust
\N3 Auto-reliable mode (MNP active)
\Q3 Bi-directional CTS/RTS flow control
&W Save configuration to non-volatile RAM


Cheers

CTK

[Darren Prior]

Hi Rex,

It looks like the modem isn't configured correctly regarding its' baud rate between the modem and the GSP port. Some modems auto-negotiate this speed (which is separate from the speed that it communicates over the phone line) whilst others have it fixed.

I'd suggest you set it to 19200 as that's the speed you have configured in your Devices files.

regards,

Darren.

[Keely Jackson]

Hi
These are some notes from the technical db and it helped me get my supra modem sorted out: sorry for bad formatting.

Requirements for modems to work on HP-UX
The following list the requirements for unsupported modems on HP-UX.

Read "Remote Access: User's Guide" section on modems, particularly page
4-16.

1) Modem should NOT ignore DTR. Modem should autoanswer when HP computer raises DTR. Modem should hang up line and disable autoanswer
and return to command state when computer drops DTR. (This is AT&D2 on Hayes modem). We do not recommend that modem do poweron reset when DTR is dropped as some modems temporarily raise CD duing reset. (In Hayes
modems, this would be AT&D3 - not recommended).

2) Modem should assert carrier detect only when there is a carrier and should
drop CD when carrier is lost. (This is AT&C1 on Hayes modem).

3) Hardware flow control (RTS/CTS) should be OFF

4) Modem should pass through BREAK

5) Modem speed should float (i.e - modem should talk to DTE at same speed as modem connects to other end. Turn OFF XON/XOFF flow control in modem. NOTE: If there are no plans to use UUCP, the modem can be set to use fixed DTE speed and XON/XOFF flow control. If the HP port supports CTS/RTS, use fixed speed w/ no flow control to get communications working. When satisfied that user can connect to port repeatedly and from multiple modems, then turn on RTS on both the computer and modem. Thus if there are problems, they can be isolated to RTS/CTS.

6) If modems connect but no data appears, turn off all compression, reliability, MNP, PEP, LAP or other advanced features and set modem to
be as dumb as possible. Get it working, then turn on advanced features.

7) Do NOT use CCITT control signals on modem or on HP computer. Note that this does not affect the ability of modem to use CCITT V.22, V.32, etc. features.

8) Remember to save modem settings in non-volatile memory on modem so modem remembers setup after power loss. (This is AT&W on Hayes modems).

NOTE: Write down the settings somewhere so you will remember them in case modem loses its settings or they are changed

I found that I needed to set even parity, xon/xoff flow control, and set &K4 (which I think was MNP auto negotiate but I can't remember).

Hope this is of some help.

Cheers
Keely

[Rex Tran]

for Vijeesh:

I tried the init string but it did not return an "OK". I disconnected with a "~."
and now I can not connect back with the 'cu' command. I gives back a responce of: Connect failed: line problem.

Are you sure the modem accepts "\"? I think it may have interperted as a new line feed and not a modem command?

I went into the GSP and did a MR to reset the remote support modem, it came back with successfully reset.
I tried again to connect but same error of line problem.

What do I do now that I can not connect back to the modem?

[Rex Tran]

Here is what is configured in the GSP:
GSP> ca

CA
This command allows you to modify the local and remote modem serial port
configurations. Current configuration settings:

Local Console Serial Port bit rate: 9600 bits/s
Local Console Serial Port Flow Control: Software
Local Console Serial Port Terminal Type: hpterm
Remote Console Serial Port Modem Protocol: Bell
Remote Console Serial Port Modem bit rate: 19200 bits/s
Remote Console Serial Port Modem Flow Control: Hardware
Remote Console Serial Port Modem Transmit Configuration Strings: Disabled
Remote Console Serial Port Modem Presence: always connected

Do you want to modify the Local Console Serial Port settings? (Y/[N])
Should anything be changed?

[Darren Prior · Accepted solution]

Hi Rex,

I'd break the init string down into the individual parts to check if your particular model accepts them. ie
ATwhatever
OK
ATnextbit
OK

I'd also suggest that the following lines that were suggested are incorrect if you are using the modem for dial-in:

&C0 Carrier Detect signal always on
&D0 Ignore DTR signal from mainframe

In most configurations that I've seen (admittedly using MultiTech modems) the modem is configured to reset when DTR drops. The DTR signal is high when a getty is running on a port, then drops when you logout. Also forcing CD could confuse matters.

regards,

Darren.

[Rex Tran]

Thanks alot! I was able to get somebody physicaly there to power-cycle the modem. I have connectivity again.

I typed in "AT&$" and the modem gave me a online help. I changed the &C0,&D0 and wrote it to nvram of the modem. I guess its a wait and see method.