Monitoring Automatic Answering; Programmed Testing; Manual Operations With Switched Network Features - IBM 3872 User Manual

Monitoring Automatic Answering
This sequence describes the normal answering of an auto-
matically answered call. If the call progress monitor (of a
modem with ACO) is turned up, audible signals accompany
the visual indications.
Indicator
On*
1. Ringing on the line
2. Ringing stops and modem sends answer tone
3. Modem Ready* (answer tone ends)
4. Operate* dims or blinks (data)
Programmed Testing
For a DTE that controls the 'test' interface line, the 3872
Modem provides a programmable local loop test. The DTE
must provide and check the test data. Refer to the descrip-
tion of the 'test; and 'data set ready' lines under "Using
Machine Considerations", in Part 3 of this manual.
MANUAL OPERATIONS WITH SWITCHED
NETWORK FEATURES
To place or answer a switched network call manually, from
a telephone at a 3872 Modem installation, it is necessary
to know whether the 3872 is equipped for automatic ans-
wering (see Figure 2-3B). It is also necessary, in the
following procedures, to know if the remote modem is
equipped for automatic or for manual-only answering.
Two sets of procedures follow the "Preliminary Setup
for Manual Operation"; one set is for use at an au to-answer
(CBS Coupler) location, and the other, at a manual-only
(CDT DAA) location. Each set contains a calling procedure
and an answering procedure. In all procedures, it is
assumed that the calling station will transmit first.
Note: The handset referred to in the following pro-
cedures is the handset of the DAA telephone. The ex-
clusion key for automatic access arrangements (a CBS
Data Coupler, or equivalent) or the data key for manual
access arrangements (a CDT Data Access Arrangement,
or equivalent) is the white key on the left cradle of the
DAA handset. When the handset is cradled, tilt it so
that the white key is operated first. CDT-equivalent
DAAs may have a different arrangement to control
talk/data mode; check with the supplier for operating
instructions.
Preliminary Setup for Manual Operation
If an automatic-answer modem is already set up for auto-
matic answering, prepare for manual operation by simply
setting the 3872 Talk/Data switch to TALK; otherwise, set
the switches as follows:
1. Power switch set to ON
2. Test/Operate switch set to OPERATE
3. Speed Select switch set to agree with the Speed Select
switch setting of the remote modem
Note: In the following procedures, confirm with the
operator of the remote modem that the switch settings
are the same.
4. Talk/Data switch set to TALK
Note: Since these are manual procedures, it is assumed
that the Talk/Data switch is set to TALK when the
modem is not actually engaged in transferring data.
5. For automatic-answer modems, CBS Data Coupler (or
equivalent) test switches in data mode (off) and the
handset cradled.
Modem Operations 2-5