S25 - Detect DTR Change

Description
S25 performs two functions. The active function depends upon the operating mode in effect. If &Q1 is in effect, then S25 is the delay in seconds after a connection has been made (and the modem goes to the online state), but before the modem checks the DTR lead. This delay allows sufficient time to disconnect the modem from an asynchronous terminal, and attach the modem to a synchronous terminal without forcing it to return to command mode. If &Q4 is in effect and bit 5 of S19 is 0 (AutoSync selected), then S25 sets the time in seconds that the modem pauses after establishing a connection. This gives the DTE time to reset its serial port to 9600 bits/s, eight data bits, mark parity, and one stop bit. This feature is not used with AutoSync II operation. For any &Qn command in effect, if in the dialing, handshaking, online, or online command state, DTR excursions from ON to OFF that last less than the time specified by S25, in 0.01 s increments, are ignored by the modem. (If &D3 is in effect, it overrides the effect of S25 and causes an instantaneous transition of DTR ON to OFF). The value of S25 does not recognize DTR ON-to-OFF transitions while the modem is in the idle state.

Type
value (seconds or centiseconds)

Value range
0 to 255; Default value: 5

Stored by &Wn
yes

Displayed by &V
yes

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