22 Jan
1999
22 Jan
'99
2:01 a.m.
On Fri, 22 Jan 1999, Colan Mitchell wrote:
Yes, exactley, it does dial and then it reports a loss
of dial tone.
Unfortunately there is no audible clue to whats going on, only whats on
the terminal screen. I don't understand how it could lose a dialtone in
this manner. The phone works fine otherwise.
What appears is basically this:
D 555-1212
555-1212
Ring
Ring
No dial
Ok, have you verified that it is in fact ringing the phone? Have you
tried dialing another line in your house (if you've got one) or a
cooperative friend's number?
Assuming that it is calling the number, which it seems to be, then what
number are you calling into? What is the carrier on the other end? A
300bps modem? A 56K V.Everything?
What would really help you is a lineman's testset. But since those cost
lots of money and you probably don't want to go breaking into telco vans
late at night to steal one like the kids used to do back in the day, you
can get yourself two .1 uF caps (240V) and two modular phones jack to rig
up a simple passive listening device.
Wire each conductor of the phone line to one of the caps. Then wire the
other leads to the modular jack. Like so:
tip (normally green wire) ----||-----\_ __
TO .1uF | |
INFORMER _|__| modular jack
ring (normally red wire) ----||-----/
.1uF
This basically isolates the DC of the phone line while allowing the AC to
pass, so you can listen in on the line without obstructing the call.
You would connect a line cord in parallel with the Informer, then connect
the other end into the contraption above. Then you can plug a phone into
the modular jack, go off-hook and then let the Informer dial while you
listen in.
Now having gotten only about two hours of sleep this morning, I just
realized I went thru all the trouble to type up this pretty circuit
diagram when all you really need is a line splitter from Radio Shack or
whatever. You could plug the phone into other jack of the splitter and
when the informer goes to dial you can pick up a phone plugged into the
other jack and listen. Isolating the line from your phone in this case is
really unnecessary. Oh well.
Anyway, try this out and let us know what turns up.
Sellam Alternate e-mail: dastar(a)siconic.com
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