Asterisk T.38 Gateway testing

Asterisk T.38 Gateway code is now in Asterisk 10

Reviewboard https://reviewboard.asterisk.org/r/1116
WIKI https://wiki.asterisk.org/wiki/display/AST/T.38+Gateway

Note: Above patch works with chan_dahdi and chan_iax. If you use other channel drivers and the T.38 reINVITE is rejected by Asterisk with 488 (approx. 4 seconds after the reINVITE was received) then the channel driver need to be changed to return -1 on T38-request indication. Just take a look at the patch how it modified chan_iax.c and apply this similarily to your channel driver.

Note: Most ATAs do not support FEC, but only Redundancy. Some ATAs just ignore FEC, other do not even work at all. Thus, usually it is a good idea to configure Asterisk to use Redundancy instead of FEC (default): add to sip.conf: t38pt_udptl = yes,redundancy,maxdatagram=400

topology 1

ATA1 --SIP+T.38-- SS7BOX1 --ss7-- SS7BOX2 --SIP+T38-- ATA2
call direction ->

ATA1(CALLER)	FIRMWARE	NAT	ASTERISK VERSION BOX1/BOX2	ATA2/GW(CALLED)	FIRMWARE	NAT	works?	notes
Grandstream HT502	1.0.1.57	yes	Asterisk 1.6.2.7/1.6.2.7	interbell IBG-130	?	yes	yes
linksys spa 2102	5.2.5	yes	Asterisk 1.6.2.7/1.6.2.7	interbell IBG-130	?	yes	yes
Patton SN4524	5.5	yes	Asterisk 1.6.2.7/1.6.2.7	Grandstream HT502	1.0.1.57	yes	yes
linksys spa 3102	5.1.10	no	Asterisk 1.6.2.7/1.6.2.7	linksys spa 2102	5.1.12	yes	yes

topology 2

ATA1 -->SIP+T.38-- SS7BOX1 --ss7-- SS7BOX2 - ReceiveFax/SendFax
outgoing ->, incoming <-

ATA1(CALLER)	FIRMWARE	NAT	ASTERISK VERSION BOX1/BOX2	spandsp/fax for asterisk	works?	notes
Grandstream HT502	1.0.1.57	yes	Asterisk 1.6.2.7/ Asterisk 1.6.2.7	0.6pre17	yes
linksys spa 2102	?	yes	Asterisk 1.6.2.7/ Asterisk 1.6.2.7	0.6pre17	yes
linksys spa 3102	5.1.10	no	Asterisk 1.6.2.7/ Asterisk 1.6.2.7	0.6pre17	yes

topology 3

ATA1 --SIP+T.38-- SS7BOX1 --ss7-- SS7BOX2 - TDM - analog Fax
outgoing ->, incoming <-

ATA1(CALLER)	FIRMWARE	NAT	ASTERISK VERSION BOX1	works?	notes
Grandstream HT502	1.0.1.57	yes	Asterisk 1.6.2.7	?
Linksys SPA 2102	5.1.12	yes	Asterisk 1.6.2.7	yes/no	only one way ata <--- tdm

topology 4

ATA1 --SIP+T.38 - PBX(asterisk) - sip proxy(kamailio)-- SS7BOX1 --ss7-- SS7BOX2 - SIP+T.38 - ATA2
outgoing ->, incoming <-

ATA1(CALLER)	FIRMWARE	NAT	PBX	SIP PROXY	ASTERISK VERSION BOX1/BOX2	ATA2	NAT	works?	notes
Grandstream HT502	1.0.1.57	yes	Asterisk 1.6.2.7	kamailio 3.0.2	Asterisk 1.6.2.7/ Asterisk 1.6.2.7	linksys	yes	?

topology 5

ATA1 --SIP+T.38--Astersk-- PRI E1-- Carrier--PRI E1-- Asterisk --SIP+T38-- ATA2
ATA1 --SIP+T.38--Astersk-- PRI E1-- Carrier — AnalogFax
call direction ->

ATA1(CALLER)	FIRMWARE	NAT	ASTERISK VERSION BOX1/BOX2	ATA2/GW(CALLED)	FIRMWARE	NAT	works?	notes
Grandstream HT502	1.0.1.63	yes	Asterisk 1.6.2.13/1.6.2.13	Grandstream HT502	1.0.1.63	yes	yes

In this tipology we have use the patch t38gateway for asterisk 1.6.2.9

N.B. The GrandStream firmware 1.0.1.63 have a new features: "Disable Line Echo Canceller (LEC)".
This features is "No" by default, and if the echo canceller is active the fax service doesn't work very well: the fax machine report is ok, but some pages are jumped.
To solve this problem you must disable the Echo Canceller on the Grandstream HT502 putting the feature to Yes