Northern UTA220/UTA220k - Manual (Page 55)

UTA220/UTA220k
6-1
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.