Northern UTA220/UTA220k manual Chapter Bis Dialer Operation, Selecting V.25bis, Bis Message Frames

V.25 bis Dialer Operation

Chapter 6

V.25 bis Dialer Operation

V.25 bis is an autodialer option used by synchronous DTEs to perform dialing and UTA220 control functions. The UTA220 supports a subset of the CCITT V.25 bis recommendation, primarily intended for the dialing and answering commands for HDLC or BISYNC modes of V.25 bis operation.

SELECTING V.25bis

The V.25 bis option can only be selected using the LCD menu or the AT@P1 command

To select V.25 bis with the LCD, scroll through the menu and select:

•CONFIGURATION OPTIONS?

•PORT CONFIG OPTIONS?

•DTE CMD AND MSG OPTIONS?

•DIALER CMDS = V.25 BSC for BISYNC mode or DIALER CMDS = V.25 HDLC for HDLC mode

To select V.25 bis with the AT@P1 command, enter

•AT@P1 = VB for V.25 bis BISYNC mode or AT@P1 = VH for V.25 bis HDLC mode.

The DTR pin is used to activate the V.25 bis dialer. When the DTR pin goes high, the dialer command setting is used to start the appropriate V.25 bis mode. When changing between V.25 mode settings, drop and raise DTR to activate the new V.25 bis dialer mode.

You can select the speed of the dialer by changing the DTE

SPEED option. When you select V.25 bis dialer operation, the

DTE SPEED is used to configure the dialer port speed.

OPERATION IN V.25 bis MODE

When the V.25 bis option is enabled, most UTA220 options still apply. Selecting V.25 bis forces the UTA220 into synchronous communications mode (regardless of the synchronous mode option). Only the DCD pin option setting applies when V.25 bis is enabled and the UTA220 is off-line.

V.25 bis MESSAGE FRAMES

The CCITT V.25 bis recommendation describes several message framing formats, including Async, BISYNC, and HDLC (bit-oriented). The UTA220 supports the HDLC and BISYNC modes. The ASCII (IA5) character set is used; the EBCDIC character set is not supported.

UTA220/UTA220k 6-1