Downloaded from Hayes BBS July 4, 1993
Permission to freely distribute.

4.0 Dial-up Access to DEC VAX Computers using Hayes Modems

This Technical Note provides instructions for connecting Hayes modems 
to DEC VAX computers running under the VMS Operating System. 
Information in this Technical Note includes configuration of the 
personal computer and of the VAX port to take full advantage of 
V-series system product adaptive compression. The configuration assumes
V-series system products are connected to the host and allows dialup 
access by both V-series and non-V-series modems.
 
Important: In all configurations, the cables used to connect the modem 
to the DTE (whether the PC or the VAX port) must support specific 
signalling requirements, with fully-shielded connectors. The cables 
appropriate for specific modem to PC connections are available from 
Hayes. For a description of each pin and its use in the various 
communication modes, see section 4.3, Modem-to-DTE Cable Requirements, 
at the end of this technical note.

4.1 Remote System Configuration

This section explains the procedures for configuring the modem attached
to the remote terminal, and special software considerations when using 
a PC as a VT terminal.

4.1.1 Terminal/PC Modem Setup

A VT terminal can access the DEC VAX over dialup lines. Because 
terminals cannot use software, the modem must be configured directly 
using the Hayes Standard AT Command Set. Set the terminal port speed to
19200 bps for V-series Smartmodem 9600 and to 9600 bps for other 
V-series system products. Because VT terminals support only XON/XOFF 
flow control, configure the modem to match this setting. Connect the 
modem to the terminal via an RS-232 cable and issue the following 
commands.

        AT&F<CR>
        AT&C1&D2&K4&W0<CR>
where:
        &F      Restores factory settings
        &C1     DCD tracks actual carrier status 
        &D2     Modem hangs up on loss of DTR
        &K4     Enables XON/XOFF flow control (V-series
                system products only)
        &W0     Stores settings in User Profile 0 * 


* Early models of the Smartmodem 2400 support a single user profile.
Refer to the user documentation to determine the capabilities; if the 
manual is unavailable, issue the command lines AT&F<CR> and AT&V<CR> 
(must be issued as two separate command lines) to view the stored 
profile(s) and telephone number(s). If the modem returns an error, only
one profile is available. To configure this modem for the desired mode,
replace &W0 with &W.

When accessing a VAX from a remote PC, communications software performs
the modem configuration and the above co