User`s manual

U.S. Robotics I-modem Command Reference

Appendix A: Alphabetic Command Summary • Page A-37

S21 10 Sets, in 10-millisecond units, the length of breaks sent from the I-modem to

the computer or terminal. Applies to ARQ mode only.

S22 17

Stores the ASCII code for the XON character.

S23 19

Stores the ASCII code for the XOFF character.

S24 150 Sets the duration, in 20-millisecond units, between pulsed DSR signals

when the I-modem is set to &S2 or &S3. The default is 3 seconds.

S25 5 Sets DTR recognition time in 10-millisecond units.

S26 1 Sets duration, in 10-millisecond units, of the delay between RTS and the

CTS in synchronous mode.

S27 0 Bit-mapped register. (See Chapter 1, Using the A

T Command Set, for

instructions about setting bit-mapped registers.)

Bit Value Result

0 1 Enable ITU-T V.21 modulation at 300 bps for over-

seas calls. In V.21 mode, the I-modem an-swers both

Bell 103 and V.21 calls, but only originates V.21 calls.

1 2 Enable unencoded (non- trellis-coded) modulation in

V.32 mode; this option is part of the ITU-T V.32 rec-

ommendation, but is rarely used.

Table AÐ1. S-register

s: Their Functions and Default Settings