[asterisk-users] ISDN30 and TDM400P + FAXing ...

[Steve Underwood]

Hi,

Gordon Henderson wrote:
> On Sat, 20 Jan 2007, Andrew Joakimsen wrote:
>
>> Assuming your PRI supports timing from the remote end (CO) which I
>> highly suspect is the case, then you should set the asterisk machine
>> to be a slave to the CO timing and then set any other interfaces  you
>> have to NOT be masters, so that the CO timing is always used. Assuming
>> you do this and disable echo cancelation then there should be no issue
>> if the entire path is low latency (IE not over the internet, not over
>> a VPN gateway and not over a WAN unless you have end-to-end QoS and
>> even then you could have latency issues, of course T.38 would solve
>> almost 100% of any issues that these would induce in your system, but
>> Asterisk does not and I higly doubt it will support anything besides
>> T.38 pass-through which wouldn't work with any sort of PSTN interface
>> you could use with Asterisk)
>
What interesting conclusions people manage to draw :-)

> It's entirely inside the same box. Call comes in on one of the PRI 
> lines and is routed out via one of the TDM400/Zap lines. No LAN/WAN/IP 
> anything...
>
> The TDM400 card, being analogue doesn't need a remote timing source 
> (it generates its own?) so I guess that'll be just fine...
How do you get the latter from the former? Unsynchronised to a common 
point means it *cannot* work with any reliability. "Just fine" should 
have been "just about useless".
>
> So it sounds like it should "just work". I'll let you know in a few 
> weeks time :)
TDM400P to E1/T1 card faxing fails by design. The lack of 
synchronisation between cards means it can *never* work with any 
reliability. The hardware will not permit it.
>
> (And I know I've asked this before, but any recommendations for a 
> basic quality PRI card in the UK? I only need a single port and it'll 
> be servicing 15 incoming lines on the ISDN30 it'll be connected to)
>
> Thanks,
>
> Gordon


Steve