A-8APPENDIX A: S-REGISTERS

Register

Default

Function

 

 

 

S19

0

Sets the duration, in minutes, for the Inactivity Timer. The

 

 

timer activates when there is no data activity on the R232

 

 

interface, and at the timeout the Business Modem hangs

 

 

up. S19=0 disables the timer.

 

 

 

S21

10

Sets, in 10-millisecond units, the length of breaks sent from

 

 

the Business 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 Business Modem is set to &S2 or &S3.

 

 

The default is 3 seconds.

 

 

 

S25

5

Sets DTR recognition time in 10-millisecond units.

 

 

 

S27

0

Bit-mapped register. (See the beginning of this appendix for

 

 

information about setting bit-mapped registers).

Bit

Value

Result

0

1

Enable ITU-T V.21 modulation at

 

 

300 bps for overseas calls. In V.21

 

 

mode, the Business Modem

 

 

answers both Bell 103 and V.21

 

 

calls, but only originates V.21 calls.

1

2

Enable unencoded (non-

 

 

trelliscoded) modulation in V.32

 

 

mode; this option is part of the

 

 

ITU-T V.32 recommendation, but is

 

 

rarely used.

2

4

Disable V.32 modulation; used for

 

 

testing HST modulation.

3

8

Disable 2100 Hz answer tone to

 

 

allow two V.42 devices to connect

 

 

more quickly.

4

16

See next page.

5

32

See next page.

6

48

Disable V.42 Detect Phase

7

128

Unusual software incompatibility.

 

 

Some software may not accept

 

 

some result codes. This setting

 

 

disables the codes and displays the

9600 code instead. The call's actual rate can be viewed on the ATI6 screen.

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Image 144
3Com 56K manual Up. S19=0 disables the timer, S21, To ARQ mode only, Default is 3 seconds, Enable ITU-T V.21 modulation at