asterisk users - Aug 2011 - T38 Fax

Anyone have any testing experience with T38 and HT-502 Grandstream?

 

I just want to confirm that t.38 is working on this device.

 

Thanks

 

 

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On 08/01/2011 12:02 PM, Robert Huddleston wrote:
> Anyone have any testing experience with T38 and HT-502 Grandstream?
>
> I just want to confirm that t.38 is working on this device.
You'd be more likely to get relevant responses if you had included the 
information about the HT-502 in your message subject :-)

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org

On 2/08/2011 1:02 AM, Robert Huddleston wrote:
>
> Anyone have any testing experience with T38 and HT-502 Grandstream?
>
> I just want to confirm that t.38 is working on this device.
>
> Thanks
>
>
Yes, it works.

I currently have latest firmware installed and it still works in T.38. I 
am using UDP transport for this device as I seem to encounter problems 
with TCP or TLS.

I am currently running Asterisk 1.8.5.0.

*Product Model: * 	  HT-502 V1.1C
*Software Version: * 	  Program-- 1.0.5.5    Bootloader-- 1.0.0.9 
    Core-- 1.0.5.2    Base-- 1.0.5.2


Some settings I have set and you may wish to check for the FXS port are;

/Force INVITE: / 	No Yes (Always refresh with INVITE instead of UPDATE)
/Send Re-INVITE After Fax: / 	No Yes


/VAD: / 	No Yes
/Symmetric RTP: / 	No Yes
/Fax mode: / 	T.38 (Auto Detect) Pass-Through
/Fax tone detection mode: / 	Caller Callee Caller or Callee
/Jitter buffer type: / 	Fixed Adaptive
/Jitter buffer length: / 	Low Medium High



You will need to ensure you are using redundancy mode instead of FEC.

I am able to send a fax via my voice provider seemingly without errors 
even though ECM is not enabled, this is because redundancy mode is 
working as expected on the outbound communication.

Unfortunately my voice provider only sends one data item in the incoming 
UDPTL hence the occasional missed line.

Here is an extract from my sip.conf

[general]
.
.
t38pt_udptl=yes,redundancy,maxdatagram=400
.
.
[906]
; Grandstream HT502 FXS Port
; Analogue FAX Modem attached
type=friend
defaultuser=906
md5secret=c5bca943c9b0cc303c496fbf9d48a48e
call-limit=1
disallow=g722
transport=udp
qualify=yes
directmedia=no
host=dynamic
context=FAX-T38
faxdetect=no
deny=0.0.0.0/0.0.0.0
permit=10.0.0.0/255.0.0.0
permit=172.16.0.0/255.240.0.0
permit=192.168.0.0/255.255.0.0

Larry.
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