[Asterisk-Users] Major problems with TDM400 and specific telephones: suggestions?

[tmassey at obscorp.com]

asterisk-users-bounces at lists.digium.com wrote on 03/22/2005 03:56:22 PM:

> On March 22, 2005 03:08 pm, tmassey at obscorp.com wrote:
> > The phone in question is what I would consider to be a good-quality GE
> > two-line cordless telephone.  Digium's guess is that it is "putting 
power
> > on the telephone line and the card doesn't like that."  They have 
given me
> > zero solution other than to use a different telephone.
> 
> I have a Panasonic 900MHz digital cordless phone that also causes 
> the TDM card 
> to have fits.  I've sent it to Digium to try and figure out what's going 
on, 
> as every single other phone and fax (probably two dozen brands between 
the 
> two) I have ever hooked up has worked just fine.  This is not a normal 
thing 
> and it may just be that the actual POTS system is able to handle their 
> particular brand of yuck.
> 
> I certainly don't blame Digium for this, but they have been more than 
willing 
> to help me correct it, especially since I am willing to get the phone to 
them 
> to test with since they seem to be unable to recreate it in their lab. 
My 
> 5.whateverGHz Panasonic digital cordless phone works great, and my 
900MHz 
> non-digital (cheapass) cordless phone works great.

I too have a cordless that works fine:  a very inexpensive Vtech cordless 
phone.  Maybe that's the problem:  we're buying phones that are of *too* 
high quality?  :)

> As I said, I've hooked up countless devices to the TDM cards and this 
> particuar phone is the ONLY one I've had trouble with.  It is perhaps a 
> corner case in the TDM design, but as I said Mark has personally been 
more 
> than willing to help fix this.

I would believe the "I'm unlucky enough to have the one phone that doesn't 
work" if there weren't so many other users with similar problems.  It's 
disturbing that with N=5 I get a phone that doesn't work.  Maybe if N=500 
I'd still have just that one phone.  But right now, I'm sitting at 20% 
failure!  :)

> As an electronics designer myself, I know how unbelievably frustrating 
it is 
> to have a customer with an issue and not be able to recreate it myself 
such 
> that a fix can be found.

As a computer programmer, I can certainly sympathize.  And unlike, say, a 
Nortel system, we're expecting to plug phones from scores of companies 
into the system without problems.  I don't envy their problem set.  But 
again, I don't seem to have these issues with other, similar, devices.

And I do have to concur with Digium's support.  I just got off the phone 
with someone at Digium about my issue and they have given me a couple of 
things to do.  We'll see if it helps, but at this point I'm happier.  I'll 
let the list know what the result is.  At least they're trying to fix it, 
rather than leaving me with "We don't know why it doesn't work, and we 
don't care..."  That's all I can ask for.

The killer is I *so* *want* this to work.  The TDM boards would really 
fill a need if they work.

Tim Massey