[comp.dcom.modems] Hayes to MicroVAX II

mataylor@tramp.Colorado.EDU (TAYLOR MARK A) (12/07/89)

We are looking for someone who has connected a Hayes-compatible modem
to a MicroVAXII.  We have tried two different modems and they both
answer and give a connect signal but do not give a login prompt from
the MicroVAX.  A termial attached to the same port at the proper
baud rate functions normally.  We suspect we do not have the 
appropriate modem to computer cable connection.  We would appreciate
hearing from someone who accomplished such a task.

Thanks,
David Lohmann
University of Colorado at Colorado Springs
lohmann@zeppo.colorado.edu
lohmann@colospgs.bitnet

hall@buffa.enet.dec.com (Dan Hall) (12/12/89)

In Article 5546 of comp.dcom.modems David Lohmann writes:

>We are looking for someone who has connected a Hayes-compatible modem
>to a MicroVAXII.  We have tried two different modems and they both
>answer and give a connect signal but do not give a login prompt from
>the MicroVAX.  A termial attached to the same port at the proper
>baud rate functions normally.  We suspect we do not have the 
>appropriate modem to computer cable connection.  We would appreciate
>hearing from someone who accomplished such a task.

You could try calling Hayes directly, pretend you have a Hayes Smartmodem, and
request that they send you their application guides for connection of modems
to DEC machines.  (Oops!  Hayes doesn't read comp.dcom.modems, do they?)  8^)

I suspect one of your problems may stem from speed mismatch.  Is the CONNECT
message saying you've connected at a rate different than the one you originated
at?  If so, you may have to enable speed buffering before originating the
call (preferred), or drop the DTE (or terminal) speed to match the connect
speed if your modem isn't speed buffering.

Assuming the MicoVAX is running VMS, I recommend that you configure the MVII
port that the modem is on with at least the following SET TERMINAL/PERMANENT
characteristics:

/MODEM/NOAUTOBAUD/HANGUP/DISCONNECT/HOSTSYNC/TTSYNC   where:

/MODEM causes VMS to interpret the modem signals,
/NOAUTOBAUD disables automatic baud rate detection.  Better to fix the data
rate between the DTE and modem, and allow the modem to do speed buffering,
/HANGUP causes VMS to drop DTR upon logout,
/DISCONNECT causes VMS to drop your process upon hangup,
/HOSTSYNC allows the host to XON/XOFF the local modem,
/TTSYNC allows the modem or the remote DTE to XON/XOFF the host.

Your guess about port to modem cabling might be right, too.  Newer versions
of VMS are fussy about getting the port characteristics and the modem settings
exactly right before things will work.  At minimum, your cabling should
support Data Set Ready (Pin 6), Data Carrier Detect (Pin 8) and Clear To Send
(Pin 5 ) from the modem, and Data Terminal Ready (Pin 20) and Request To Send
(Pin 4 ) from the DTE.  Naturally, you also need Signal Ground (Pin 7),
Transmit Data (Pin 2), and Receive Data (Pin 3).

Try configuring your 'Hayes-compatible' modem on a VAX serial port with
the following AT commands:  AT &F E0 Q1 &C1 &D2 &S1 S0=2 &W    where:

&F	First, go to factory defaults
E0	Disable command state character echo
Q1	Disable results codes
&C1	DCD track data carrier from remote modem
&D2	Hang up modem on deassertion of DTR
&S1	Operate DSR according to EIA-232-D specifications
S0=2	Answer on second ring
&W	Write this configuration to non-volatile memory

I have a DEC 'Hayes compatible' modem on a VAXstation 2000 serial port,
but I use it in DMCL (Digital Modem Command Language) - MUCH more user
friendly!!

Good luck.  Let me know if I've been any help.

Regards,

-Dan Hall

    
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     | Dan Hall                                                  |   
Email: hall@state.enet.dec.com               |
     | Digital Equipment Corp.                          |      -or-
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