Modem Modulation V.32bis

Unanswered Question
Apr 30th, 2009
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We have a AS5300 with NP108 DSP cards installed. POS terminals dialup to the AS5300 and fork a telnet stream to a host on a specific port. Here is a snippet of how my lines are configured.

modemcap entry LOPEDS:MSC=&F&D2s0=0s64=4S15=0s16=0s17=0S21=0S22=0S23=0S24=0S52=0S53=0

line 2/00 3/107

modem InOut

modem autoconfigure type LOPEDS

autocommand telnet x.x.x.x 1234 /quiet /stream /noecho

transport preferred none

escape-character NONE

The modem modulation we would like to use is V.32bis. However, it seems that the negotiation process is very slow.

*Apr 30 15:58:35.979: Modem State event:

State: Connect

*Apr 30 15:58:36.027: Modem State event:

State: Link

*Apr 30 15:58:37.807: Modem State event:

State: Ranging

*Apr 30 15:58:43.343: Modem State event:

State: Half Duplex Train

*Apr 30 15:58:48.271: Modem State event:

State: Train Up

*Apr 30 15:58:48.271: Modem State event:

State: Steady

*Apr 30 15:58:48.275: Modem Static event:

Is there any documentation on what is being negotiated during the Link,Ranging,and Half duplex Train? Is it possible to reduce the negotiation time from 13seconds to 3 seconds?

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paolo bevilacqua Sat, 05/02/2009 - 09:28
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The command to do that are documented in "modem at command reference", you configure an initialization string in modemcap like that. The details varies depedning the HW that you have.

bdavidsson Sat, 05/02/2009 - 16:05
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By default, modems negotiate the speed upon connection. You can set the speed (modulation) as fixed on either end of the connection, the dial-in modem or the receiving end. This will shorten the negotiating time.

paolo bevilacqua Sat, 05/02/2009 - 16:13
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Answer above is incorrect, on cisco AS5xxx platforms the interface speed does not influence limiting connection standard, for which you have to use use modemcap customization as indicated by my reply above.


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