[Asterisk-Users] modem to modem calls through asterisk

[Gary Mart]

On Tue, Nov 25, 2003 at 05:51:37PM -0600, Don Pobanz wrote:
> Modem connect speeds on calls through * seem to be lower than calls 
> made through the telephone company lines or our old Rolm PBX. All data 
> calls have 2 wire analog modems on both ends.
> 
> For my set up I have channels of a Zhone channel bank tied to 2 modems. 
> The Zhone channel bank interfaces my * server with a T400P card.
> modem  --- Zhone Channel bank - * via T400P card - Zhone channel bank - 
> modem
> 
> In extensions.conf I have added the 'd'ata option.
> exten => 333,1, Dial(Zap/19,,d)
> 
> In zapata.conf echo cancel has been turned off and I have experimented 
> with different size jitterbuffers, none of which seem to help.
> 
> I couldn't find anything else in the archives. Other suggestions?

Could you be suffering from an extra digital <-> analog conversion?
Each conversion between analog and digital hurts performance.  (56k
modems are faster than 33.6 modems because there is no digital <->
analog conversion on the ISP side.)

I have PRI lines and just few days ago, I posted a reply to subject:
"Echo Cancellation, TDMoE fails, X100P works" that includes a detailed
explanation of my setup that runs v.90 modems at full speed through *.

Gary

> 
> Don Pobanz
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