S122 - V.13 Selection
Description
S122 selects V.13 operation if the modem is in &Q1, &Q2, or
&Q3 mode. V.13 allows a full-duplex modem to signal to the distant end when
to turn its RLSD signal on or off.
The &R command controls whether the CTS signal is always on or tracks RTS.
However, having CTS always on does not affect the recognition of transitions
on RTS to cause transmission of V.13 simulated carrier control signals.
The &C command is obeyed as well. If RLSD is strapped on with &C0, this
overrides indications on circuit S109 (RLSD) of received V.13 carrier-on/carrier-off
patterns (which is passed on to the DTE only in &C1 mode).
The S26 RTS-to-CTS delay is in addition to the delay which the modem introduces
to transmit the V.13 carrier-on signal (which is only 8 bit-times). If RTS
is turned off for less than 128 bit-times, it is treated as if it had remained
off for 128 bit-times (i.e., CTS deferred) until the full 128 bit-times
of the carrier-off signal have been sent.
Type
value
Value range
0-3; Default value: 0
Stored by &Wn
yes
Displayed by &V
no
Values
Value Description
0 Disables use of V.13.
1 Transmit V.13 signals when RTS changes state
2 Recognize V.13 signals in received data and switch RLSD accordingly
3 Both 1 and 2
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