Telecom PTC - SIP Trunking

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bender

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Reply # 287207 5-Jan-2010 17:22
I wonder how many 7940's and 7960's still out there in production use? The 7941/7961 are basically dead now, and any new hardware purchased would be 7942's/7962's as they're the same price as the x1 models. I've seen a few x0 models around but they'd probably be close to being traded in for new kit...

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Reply # 287224 5-Jan-2010 18:12
bender: I wonder how many 7940's and 7960's still out there in production use? The 7941/7961 are basically dead now, and any new hardware purchased would be 7942's/7962's as they're the same price as the x1 models. I've seen a few x0 models around but they'd probably be close to being traded in for new kit... Given that Cisco haven't end of saled them yet and they are cheaper than the 79x2's I would doubt if many of them have been replaced yet.

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Biddle Corp

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Reply # 287247 5-Jan-2010 19:18
Thanks for the clarifications! *Need help configuring your Linksys ATA or IP Phones for New Zealand? Check my blog post

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Reply # 290188 15-Jan-2010 08:34
The TELECOM SPECS only stipulates G711 alaw so Telecom's gateway network must only be supporting E1 trunks. At one stage , you will require a call from SIP to PSTN . Therefore , a use of different codecs and Telecom not supporting a variant of codecs will introduce a codec mismatch . This can introduce one-way speech issue /or call drop-out . A SIP PBX with SIP phones must also support G711alaw as a fallback in case of PSTN calls. We are still in a world of mix technologies here ...SIP and PSTN . I must also admit that using G729/G722 will offer a pure crisp voice quality but fallback to G711a law isn't that bad at all.

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Reply # 290296 15-Jan-2010 12:57
jusjon: The TELECOM SPECS only stipulates G711 alaw so Telecom's gateway network must only be supporting E1 trunks. At one stage , you will require a call from SIP to PSTN . Therefore , a use of different codecs and Telecom not supporting a variant of codecs will introduce a codec mismatch . This can introduce one-way speech issue /or call drop-out . A SIP PBX with SIP phones must also support G711alaw as a fallback in case of PSTN calls. We are still in a world of mix technologies here ...SIP and PSTN . I must also admit that using G729/G722 will offer a pure crisp voice quality but fallback to G711a law isn't that bad at all. I can't see G729 offering "pure crisp voice quality" as it mobile voice quality at the best.. Regards, Old3eyes

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Reply # 290298 15-Jan-2010 13:01
G729 is awful. My point jusjon is that G711a only makes life hard (as per my previous posts about issues with voicemail platforms etc where you'd need to record prompts in both formats etc). Providers like CallPlus, WorldxChange, Orcon etc all manage to handle customers using both alaw and ulaw, so would it really kill Telecom to handle ulaw as well at their SIP PSTN gateway?

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Wannabe Geek

Reply # 290314 15-Jan-2010 13:51
I agree with all your points . . . I may have to agree that its a technical limitiation on Telecom's SIP PSTN gateway to handle ulaw.

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Reply # 290319 15-Jan-2010 13:59
When sending calls to countries using ulaw do they force those countries to use alaw?

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Wannabe Geek

Reply # 290323 15-Jan-2010 14:07
They don't force those countries to use alaw as PSTN International switches ( a.g.a. Gateway switches ) in a TDM world will have capabilities to interface with E1( alaw ) / or T1 ( ulaw ) . This is a case , I believe , for a SIP nwk interfacing to a PSTN nwk ( using a law only ) . The SIP-PSTN gateway must only be supporting a-law as the case maybe .

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