Helmholz 700-751-HSM11, Руководство пользователя, Страница: 39 / 99

Helmholz Modem 56k 4.1 39
5.13.2 Going off-hook on account of a telephone connected in
series
If a telephone connected in series goes off-hook during an ex-
isting modem connection, the modem will immediately ter-
minate the connection.
The telephone is connected to the line and receives a dialing
tone.
In the registry S86, the value is set to 25.
When the phone connection is terminated, the modem will
not establish a new connection.
Changing the loop voltage to detect the function – Off-hook
on account of a telephone connected in series (
U2
) – can be
set with the help of
AT
commands.
Note: The detection starts immediately after the
handset is picked up. To access the exchange,
simple analogue phone systems often connect
the modem per contact directly with the ex-
change, which results in a strong change or
polarity reversal of the loop voltage. For some
analogue phone systems, this may result in an
erroneous detection. Off-hook detection is
therefore not recommended in connection
with analogue phone systems.
U2
Loop voltage prior to
start of connection.
Time
Voltage
Loop voltage after a
phone in series is
picked up.
ATS86=25
AT-TTE=U1, U2, U3