[AusNOG] Cisco SPA - Fax in Australia

[McDonald Richards]

RTP at 10ms is asking for trouble. Most of the IP voice carriers in AU run 20ms where they can and 30ms on codecs that have that as the minimum. Using values other than this, depending on your provider can lead to transcoding which will reduce call quality.

One of the biggest fax issues I've seen has been ignorance of pcmu vs pcma. T.38 compatibility has improved the last 10 years but still
lacks support on some wholesale carrier interconnects in Australia so can be patchy. Client stacks are a lot better than 5-6 years ago when I did a lot more voice work.

As far as compatible transport goes, pcma at 20ms over a good quality IP network should get you most of the way there. 

Macca


> On 22 Apr 2014, at 10:21 pm, "dean at faktortel.com.au" <dean at faktortel.com.au> wrote:
> 
> Hi Joe
> 
> You can try these settings.
> I use these settings for pap2t and spa3102....etc. should be similar to
> spa122. if i dont have a t.38 gateway
> 
> 3 Way Calling: no
> Echo Canceller: no
> Silence Suppression Enable: no
> Call Waiting: no
> FAX Disable ECAN: NO.
> FAX CED Detect Enable: YES
> FAX Enable T38: NO
> FAX T38 Redundancy: 0
> FAX Tone Detect Mode: Caller or Callee
> Network Jitter: Very High
> Jitter Buffer Adjustment: Disable
> Preferred Codec: alaw
> Fax Passthru Method: reinvite
> 
> These 2 make a big difference for me..
> 
> RTP Packet Size to 0.010
> FXS port impedance to 220+820|| 120NF
> 
> 
> 
> 
> Regards
> Dean
> faktortel
> 
> 
> 
> -----Original Message-----
> From: AusNOG [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Joseph
> Goldman
> Sent: Tuesday, 22 April 2014 1:32 PM
> To: AusNOG at lists.ausnog.net
> Subject: [AusNOG] Cisco SPA - Fax in Australia
> 
> Hi list,
> 
>  Trying to have some luck using faxes behind Cisco SPA ATA's, in particular
> testing with an SPA122. I can get the unit to detect its a fax coming
> through, but often they don't begin communication between the
> 2 endpoints, or if by luck they do I get a comm error.
> 
>  T.38 is enabled, NSE enabled, also tried with no NSE enabled.
> 
>  Anyone had luck getting these units to work in AU ?
> 
> Thanks,
> Joe
> _______________________________________________
> AusNOG mailing list
> AusNOG at lists.ausnog.net
> http://lists.ausnog.net/mailman/listinfo/ausnog
> 
> _______________________________________________
> AusNOG mailing list
> AusNOG at lists.ausnog.net
> http://lists.ausnog.net/mailman/listinfo/ausnog