[VoIP] Adtran outpulsing

Fri Jun 1 06:49:22 CDT 2007

Max,

Excellent thought(s) and quite logical.  I use a Digium T400P clone of some
sort - I'd have to look to see who made it.  I can't remember what Russ is
using, but maybe that can shed some light if he's using a different board.
I know he was using an Adtran like me with the same FXO.

Lee

-----Original Message-----
From: voip-bounces at ckts.info [mailto:voip-bounces at ckts.info] On Behalf Of
ikjtel
Sent: Thursday, May 31, 2007 11:05 PM
To: Voice Over IP Tandem for Analog Switches
Subject: Re: [VoIP] Adtran outpulsing

FWIW, the X100P uses a different low-level driver
(wcfxo.c) than channel-bank ports use (wct1xxp.c et
al.), and the Digium TDM400 uses yet another one
(wctdm.c) although all of these in turn rely upon
zaptel.c for the generic processing...  Then again SIP
has yet another driver (and is even more different in
that user-space [asterisk] speaks to SIP devices
differently  - chan_sip.c instead of chan_zap.c) All
clear??? :-)

It is easy to hear the irregularity in the outpulsing
(at least it was some time ago when dialling thru
Lee's system which had the "hearpulsing" patch
applied)...

The way in which the signalling is conveyed in the
Adtran-FXO case is by way of the "RBS bits"
(robbed-bit signalling) using the A and B bits in the
T1 frames.

Inasmuch as the X100P's seem to work OK, it is
tempting to rule out zaptel.c as being the culprit. 
This leaves wct[e]xxxp.c, the T1 itself and the card,
and the Adtran as possible suspects. One would *hope*
that the Adtran would be somewhat more robust than to
fall into such a stupid bug, but it's possible I
suppose.  The T1 and card are too stupid to be prime
suspects, but again it's possible.

By amassing more data points we might be able to
remove one or more of the remaining suspects from the
list.
I think it's probably safe to say that SIP is a
different enough beast that it's not in play in this
elimination excercise.  However, if someone has a
genuine TDM400 with FXO's (probably the Varion
"clones" would only add to the confusion here) it
might provide an interesting data point as to whether
they have the irregularity or not...  Likewise, if
someone has another brand of channel bank FXO other
than an Adtran one it would be *very* interesting to
see if the problem occurs there as well...  (My own
unsubstantiated suspicion is that it would).

Unfortunately my channel banks only have FXS, and the
one time I looked to see how hard it might be to rig
up a test environment, it seemed to be unfeasible.  It
didn't appear that the signalling bits worked the same
way (or similarly enough) ...

More data / feedback is welcome, of course...

Best

Max

p.s. One *could* open a trouble ticket with Asterisk,
I suppose ;-)

--- Lee Spenadel <lee at spenadel.com> wrote:

> The Adtran problem may not be apparent in all
> situations.  Russ Price did
> some testing after my reported problems with
> consistent dial pulsing from
> the Adtran FXO to my SxS.  Russ' and my switches
> were somewhat intolerant of
> the timing of the Adtran pulsing.  Russ tried
> modifying the pulsing
> make/break times in asterisk with no change in
> pulsing to his SxS.   In my
> case it lead to mis-dialing of extensions.  It
> doesn't do this all of the
> time.  It's somewhat intermittent.  When I placed a
> WildCard X100P in my
> Asterisk box and set it up to pulse to my SxS, all
> worked fine.
> 
> I guess the bottom line is that the Adtran FXO does
> pulse out the digits,
> but depending on the tolerances of your switch, you
> may or may not have a
> problem. 
> 
> Lee
> 
> -----Original Message-----
> From: voip-bounces at ckts.info
> [mailto:voip-bounces at ckts.info] On Behalf Of
> Jonathan Kay
> Sent: Thursday, May 31, 2007 7:41 AM
> To: Voice Over IP Tandem for Analog Switches
> Subject: Re: [VoIP] Adtran (was Cisco 3810)
> 
> Lee Spenadel wrote:
> > So was I.  How much was it?  I'm wondering if that
> would be a nice device
> to
> > use for FXO in lieu of the Adtran given the
> outpulsing problem toward my
> > SxS.
> >
> >   
> 
> Is there a definite problem with Adtran channel
> banks and rotary dialling?
> I'm more than a bit hacked off if that's the case,
> after paying loads of 
> shipping to the UK and big bucks to obtain an FXO
> loaded Adtran.
> I've still not had time to set the thing up so far.
> 
> Jon K
> _______________________________________________
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