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CHAPTER 10: S-Registers
Register
Range
Default
Function
S23
—
—
Bit-Mapped Options.
Bit
Option
Val Descrip Cmd
0
Obey request
0
Disabled &T5
from remote
1
Enabled &T4
modem for
remote digital
loopback test
1-3
Assumed DTE
0
300 bps
rate
1
600 bps
2
1200 bps
3
2400 bps
4
4800 bps
5
9600 bps
6
19.2 kbps
4,5
Parity Option
0
Even
1
Space
2
Odd
3
Mark
6,7
Guard Tones
0
Disabled &G0
1
550 Hz
&G1
2
1800 Hz &G2
S24
—
—
Not used.
S25
0 - 255
5
Async DTR delay. Sets the duration (in
hundredths of a second) that DTR must be
dropped in order to be interpreted as a DTR
loss. Allows the modem to differentiate
between a random glitch and a true DTR
loss.
In most cases, the default value can be
used. The S25 register is useful for setting
compatibility with older systems running
under older operating software.