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? Don Pobanz
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 > _______________________________________________ > Asterisk-Users mailing list > Asterisk-Users@lists.digium.com > http://lists.digium.com/mailman/listinfo/asterisk-users
Replacing my zhone channel bank with an Adtran 750 has fixed my modem - modem connect speed problems. I don't know whether this is something unique to zhone channel banks, my particular zhone channel bank or my installation/configuration. Regardless, it is good to have identified the problem. Don Pobanz On Tuesday, November 25, 2003 5:52 PM, Don Pobanz [SMTP:dpobanz@hastingsutilities.com] wrote:> Modem connect speeds on calls through * seem to be lower than calls > made through the telephone company lines or our old Rolm PBX. Alldata> 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 haveexperimented> with different size jitterbuffers, none of which seem to help. > > I couldn't find anything else in the archives. Other suggestions? > > Don Pobanz