3Com PC Card User Manual - page 43

S Registers

39

S27

Bit-mapped. V.25ter not enabled. Storable.

Bit 3,1,0. Communication mode (&Q, \N CMD)

■

0 = Normal asynchronous

■

1 = Sync mode 1

■

2 = Sync mode 2

■

3 = Sync mode 3

■

4 = Direct

■

5 = MNP

■

6 = MNP/V.42

■

7 = V.42

■

V.25ter enabled

Bit 3. Not used

■

Bits 1-0. Communication mode (&Q, \N command). 1 = Lease line

■

00 use S36 communication mode setting

■

01 synchronous mode 1

■

10 synchronous mode 2

■

11 synchronous mode 3

Bit 2. Leased line (&L CMD)

■

0 =GSTN

Bit 5,4. Synchronous transmit clock source (&X CMD)

■

0 = Internal

■

1 = External

■

2 = Derive from receiver (slave)

Bit 6. Bell / CCITT (B CMD)

■

0 = CCITT

■

1 = Bell

Bit 7. Reserved

S28

Bit-mapped. Storable.

Bit 1,0. Error Correction Maximum Block Size (\A CMD)

■

0 = 64 bytes

■

2 = 192 bytes

■

1 = 128 bytes

■

3 = 256 bytes

Bit 6,5,4,3,2. V.42 detection period (T400) in 50 milliseconds increments (%G CMD)

■

0 = Infinite

■

1 to 155 = number times.05 second

Default = 16 for.8 seconds

Bit 7. ODP/ADP (&A CMD)

■

0 = Do not use ODP/ADP when initiating a reliable V.42 handshake 

■

1 = Use ODP/ADP when initiating a reliable V.42 handshake