We have a modem in Ljubljana which won't pick up when called from
another modem. It doesn't see the RING and the calling modem gets BUSY.
If I pick the phone up and dial then after S0 number of rings the
Ljubljana modem answers (and results show S0 RINGs).

From the Ljubljana modem I can call the modem here no problem and have a
data session just fine between the two modems.

Is this more likely to be a phone system problem than a modem problem?
How do modems detect busy, anyway? Just by listening to tones or is it
signalled some other way by the phone system?

-- tim

Tim Streater wrote:
The answering modem should have no idea who or what is calling. It
should
answer after X # of rings regardless. The calling modem detects a
busy the
same way you do, ie; what ever is the standard busy signal.

There are several possibilities here, some due to Country Code
differences:

1. The calling modem may think that the *ring* signal it hears is
what it thinks is a Busy. Can you call other locations OK ?

2. The modem is dialling "too fast", causing the telco switch to
signal Busy, as in "the call did not go thru". Can you tell if
ringing is actually present at the ans. modem, when called by the
calling modem ? One way would be to plug a telephone in the
answering line and call it from the calling modem.

--reed

"Reed" <reedh@rmi.net> wrote in message news:42EAD80E.A0588BE8@rmi.net...
They listen to detect busy signals. They have firmware programming (for full
hardware onboard controller modems) which tells them what a busy signal
should sound like so if the modem is used in a country other than the one
its designed for (without being reconfigured first where possible), then
there may be problems such as you're experiencing due to the different
tones/cadences used. Software modems are often more flexible in this regard
and commonly adjust to different countries through control panel
configuration utilities.

I agree with this one - I have had a USR Sportster do exactly this to me in
New Zealand even though it was obtained through the official USR
distribution channels there! The official solution from the distributor was
to configure it for blind dialling by putting an X3 in the additional
commands box of windows. Although this got around the problem I was
experiencing, it also meant there was no legitimate busy signal detection.
Unfortunately the manufacturer didn't have New Zealand (or Global) firmware
for the modem (only US Firmware) so I returned it for a refund and bought a
much cheaper GVC modem (which worked perfectly for a fraction of the price -
I still have it today and it has global firmware which can be configured for
different countries). If the OP provides details of the modem make and
model, people here may know how to configure it for use in Slovenia.
<snip>
Paul

In article <42EAD80E.A0588BE8@rmi.net>, Reed <reedh@rmi.net> wrote:

OK OK. It turns out I was dialling the wrong number. This in spite of
some checks to verify I was dialling the right one.

We still have a problem where our NOC in Paris can't reliably reach the
modem, but that's probably a different story. Sorry to waste everyone's
time.

-- tim