3Com 3C900B Installation And Operating Instructions Manual page 137

Register Default
S22 17
S23 19
S25 20
S27 0
T
ECHNICAL
Function
Stores the ASCII decimal code for the XON character.
Stores the ASCII decimal code for the XOFF character.
Sets the duration, in hundredths of a second, that DTR must be dropped so that the
modem doesn't interpret a random glitch as a DTR loss. (Most users will want to
use the default; this register is useful for setting compatibility with older systems
running under older operating software.)
Bit-mapped register setup. To set the register, see instructions for S13.
Bit Value Result
0 1 Enables ITU-T V.21 modulation at 300 bps for overseas calls; in
V.21 mode, the modem answers both overseas and domestic
(U.S. and Canada) calls, but only originates V.21 calls. (Default
Bell 103)
1 2 Enables unencoded (non-trellis coded) modulation in V.32 mode.
2 4 Disables V.32 modulation.
3 8 Disables 2100 Hz answer tone to allow two V.42 modems to
connect faster.
4 16 Enables V.23 fallback mode.
5 32 Disables V.32bis mode.
6 64 Disable V.42 selective reject.
Q R
UICK EFERENCE
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