5902 Bell 202 Modem Hardware Manual
October 19, 2007
5.3.3 Half Duplex Slave for Constant Carrier Master
Use this configuration for a slave modem, connected to a full duplex, constant carrier, master
modem (see above). Switches not shown in the table below are either ignored or are not critical.
Note: Constant carrier, half-duplex operation should not be selected if two-wire mode is used.
Adjust these switches to transmit a longer carrier
before data transmission commences. Ensure this
delay is longer than the master modem’s CD delay,
plus any propagation delays in the communication
system.
These switches must be closed for constant carrier
reception.
Add anti-streaming as required to protect the
network against excessive transmission length. The
maximum message length determines anti-
streaming time.
Use the shortest SCT time that prevents carrier
turn-off noise. This will normally be achieved with
the recommended settings. The SCT time can also
be used to transmit a quiet period at the end of
each message if the receiving modem does not
recognize soft carrier turn-off.
Close CSH if the RTS signal on the DTE flickers.
Also close CSH to transmit an extended MARK
after each transmission.
Half duplex must be selected.
Close switch to engage tone transmission test
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