[on-asterisk] Need some advice to resolve problems with an new DIY PBX

[Lew Pitcher]

Hi, crew

You might not be the best group to ask (and if so, please let me know),
but I recently purchased a chinese clone of the Sangoma TDM410P 4port
analogue telephony card (1 FXO & 3 FXS), and I need some advice on it's
setup.

I have Asterisk 18.1.0 installed (under 64bit Slackware Linux 14.2), and
the correct DAHDI 2.11.1 drivers, and the card mostly works; I can call
between stations properly. I have two outstanding issues:
1) the FXS ports don't seem to supply the proper current to activate the
ringers on my (admittedly 30-year-old) analogue phones, and
2) the FXO (for the most part) reports a RED alarm when connected to the
PSTN (at my demarkation point).

For problem 1, I've encountered reference to the "boostringer" option on
the wctdm24xxp driver. I haven't tried it yet. FWIW, the TDM410P clone
does not have the additional power-supply connection available on the
original device; I don't know that the boostringer option /can/ do
anything.

As for problem 2, I /have/ managed to complete one incoming call over
this FXO; it stayed out of alarm long enough to do that. However, once
it goes into alarm, I can neither make outgoing calls, nor accept incoming
calls. So the alarm condition needs fixing. I suspect that part of the issue
is that I connect to the back-end of a phone-based security-alarm system,
which might influence the electrical characteristics of the FXO interface.
Additionally, as I'm just trying this system out, I'm using an over-long
extension between it and the POTS connection.

Does anyone have any suggestions on how to address my two issues?
I appreciate any help you can give.
Thanks
--
Lew Pitcher
"In Skills, We Trust"
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[Lew Pitcher]

Hi, John

On Sun, 6 Dec 2020 20:09:16 +0000, John Pennington wrote:

> On 06/12/2020 20:00, Lew Pitcher wrote:
> > Hi, crew

> >
> > I have two outstanding issues:
> > 1) the FXS ports don't seem to supply the proper current to activate the
> > ringers on my (admittedly 30-year-old) analogue phones, and
>

> 1> The original TDM cards have a molex connector to take a power feed
> from the PC to drive the FXS ports

Well, I solved this problem today. As I mentioned, I'm testing with a couple of 30+ year old analogue handsets, and I suspected that the ringer power requirements that these handsets had were too much for the clone TDM410P. It turns out that, with a more modern handset, the card meets the handset power requirements. /AND/, if I enable the "boostringer" option in the wctdm24xxp driver, even the older handsets get enough power to ring properly.

For my purposes, I count this problem solved; I don't intend to use this DIY PBX in an environment that has any ancient handsets, and even if I do, I can ring them with "boostringer=1"

> 2> not sure, never had any issue with Digium/Sangoma parts

I don't think that this problem is a card or driver problem. I haven't performed any diagnosis on it yet, but (as I managed to make an external connection once on it) I believe it to be a telephone wiring issue, likely with the over-long extension that I had to wire up to connect the system to the phone line. I'll try another extension, and/or moving the phone system closer to the demarcation point.

> My suggestion is to get a used TDM 400 (Digium/Sangoma card and modules)
> off Ebay, they are pretty cheap and do work as expected

Thanks for the suggestion. I've got nothing but time to play with my clone card (pandemic lockdown, and I'm retired), but if it really doesn't co-operate with me, I'll seriously look into the eBay solution. FWIW, some of those eBay cards seem to come from the exact same vendor as I purchased my clone card from. I'll have to be extra-cautious when ordering, so as to get a genuine device.


Thanks again for the advise.