As Dave and others suggest, first find some dial tone and make sure it
is getting to the card,
(use an old analog phone as a "Butt Set")
If you have a ground start trunk it will only "start" or get dial tone
if you ground the
"Tip" (or one side of the pair) for less than a second.
I haven't seen a ground start for about 20 years so its very unlikely
that this is the problem.
The analog telephone is a current driven device when on-hook there is
48volts DC on the line
When you go off-hook a load of 600 ohms completes the "loop" and the
voltage will drop to about 12 to 24 volts
Using Ohms Law (Amps = Volts /Ohms) the current drawn is 24volt drop
/600 ohms = 40-60 ma
it is this series current that is detected as an off hook signal and
that tells the exchange to supply dial tone
The audio signal is supposed to be at 0dbf or approx 0.7 volts peak to
peak but normal speach will be less than that.
Since the audio is true duplex a phone will have a special phase filter
which is designed to stop you hearing your own voice
but allows some "talk back" so you can hear yourself and know that the
phone is working (when you speak)
When an incoming call arrives the on-hook telephone sees about 90 volts
AC at 30 cps with the caracteristic
cadence. in the analog world this voltage is isolated from the line at
the phone by using a simple capacitor in series with a
machanical bell, for the standard analog phone (often called a 2500 set)
this ringer has a load equivalent of "1"
Many ATA's and FXS cards have a problem driving such high loads but
fortunately modern phones use an electronic ringer
that has an equivalency of much less than "1" This number is often
printed on the underneath of the phone.
The pure simplicity of this system is why it endured for over a hundred
years.
All this and $2.50 will buy you a cup of coffee at Starbucks
Henry
Dave Donovan wrote:
Well, you learn something new every day. I had no idea that
connector was called an RJ-21. I've always called it a 50-pin
amphenol. Cool.
Anyhow, are you pretty sure that you've got the right pinout? My
first thoughts go to wiring. If you can get the back off the
connector, you should be able to connect a phone to the
blue-white/white-blue pair (pair 1) and get a dial tone from the bell
service.
I wonder if what the Asterisk logs are telling you is that it's gone
offhook. It may well be going offhook and sending DTMF on a line
which has no signal from bell. When you dial in to one of the lines,
does the Asterisk box report that it detects ringing?
Just to eliminate one outside possibility: I think there are two
versions of this card, an FXO version and an FXS version. I think you
need the FXO for what you're describing. If the card is only
populated with FXO modules, you shouldn't need the power connector
from the PC, the PCI bus should be enough. You probably would have
noticed ZTconfig freaking out on you if this was set wrong so, like I
said, it's pretty unlikely.
I've got the tools and connectors that are required to trace a wiring
problem so if you think that might be the cause of your issue and
you'd like me to come on site, we can arrange that. Otherwise, keep
posting and we'll get to the bottom of it.
Dave
On 6/6/06, Mansel Lavery <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Asterisk User Group,
I've recently acquired a TDM2400 for my office and have setup the
Asterisk
network internally without a problem. However, I cannot seem to get an
outside line using the TDM2400 though the Asterisk logs and phone
confirm an
ongoing call.
Our line provider is Bell who runs an RJ-21 cable into a patch
board which
then runs another RJ-21 into the card.
Has anyone had similar problems with Bell? I am currently using Kewl
signaling and wondered if they used a different type or required a
longer
wait before attempting to dial.
Thank you
Manny
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--
David Donovan
Consultant
Fulcrum Solutions
--
Henry L.Coleman [ VoIP-PBX ] Tel.1 866 415-5355 Ext.301
