Specifications

CSU/DSU MS DBU

V.25

BIS

OMMANDS

When configured for the V.25 bis option, the CSU/DSU MS DBU accepts in-band

dialing and configuration commands from both synchronous and asynchronous

DTE ports.

The V.25 bis option supports the following protocols:

• SDLC

• Bi-Sync

• Asynchronous

SDLC Option

Character Format

• Data bits - 8

• Parity bit - Ignored

Command Structure

[F][A][C][V.25 bis COMMAND][FCS][F]

The address field [A] is FFH. The control field [C] is set to 13H except for cases of

multi-frame responses. For this case, the control field is set to 03H in all but the last

frame. The 03H in the control field indicates that other frames are to follow, while

the 13H in the control field indicates the final frame.

Bi-Sync Option

Character Format

• Data bits - 7

• Parity bit - Odd

Command Structure

[SYN][SYN][STX][V.25 bis COMMAND][ETX]

Asynchronous Option

Character Format

• Start bit - 1

• Data bits - 7

• Parity bit - Even

• Stop bit - 1

Command Structure

[V.25 bis COMMAND][CR][LF]