Black Box MD1641A Manuale Utente

Once you press the switch, the tone you hear should change to another
pitch, or change into a rough-sounding scrambled noise. You then
replace the telephone handset in its cradle, and your data
communications begins.

Note that the Series II Modem may call manually via the keyboard
command 

, or by pressing the Voice/Data switch on the modem's

front panel downward. To force the Modem to automatically answer
calls, either type 

or press the Voice/Data switch on the modem's

front panel upward.

The Series II Modem can be used as an automatic answering modem.
No special modifications or settings are required other than making
sure that the Auto-Answer select switch is set to Auto-answer enabled
(DIP-Switch #5 UP).

The Modem, when in its idle state, is set for Originate mode frequencies.
An incoming ring signal automatically switches the modem into Answer
mode.

You can program the modem to answer a call after a certain number of
rings using S-Register S0 (see Chapter 6). Refer to Section 4.10 for the
handshaking procedures used by the Modem when in automatic answer
mode.

In many originate-only applications, you may wish to disable the
automatic answer capability of the modem. If a telephone set is
connected to the modem, you may wish to receive incoming calls in 
a voice mode for normal voice conversation. If auto-answer is not
disabled, all incoming calls are answered by the modem, preventing
voice communications. To disable automatic answer, place DIP-Switch
#5 to the DOWN (Disable Auto Answer) position (refer to Chapter 9).

Another way to disable automatic answer is to use S-Register S0 to
configure the modem to answer on the

th ring, where

equals zero

(0). Another alternative is to have the modem answer after five or six
rings, which gives you time to answer it manually if you wish. (See
Chapter 6

for S-Register information.)