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best dial back modem

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Occasional Contributor

best dial back modem

We are looking to get a new modem to dial in to a HP3000 937 via DTC. which type is best for this please?
2 REPLIES
Honored Contributor

Re: best dial back modem

Hayes modems work okay on a DTC. Successful DTC modem operation requires correct configuration, cabling, and correct internal modem configurations.

DTC CONFIGURATION:

If your 937 system is host-based DTC (DTCs managed by NMMGR), make sure in NMMGR you use a profile name with the modem behavior option set to 1 (1=DCE).
If your 937 system is PC-based DTC (DTC managed by a PC running Openview DTCMGR), then make sure the DTC port configuration in DTCMGR for Dial in Modem, include Standard DCE for modem behavior.

MODEM CONFIGURATION:

These are Hayes V-Series 9600 Baud modem's settings for connection to a DTC 3000 machine. These setting will work for most
non-hp Hayes compatible modems under 14400 baud.

First set up the modem with a terminal connected directly to the modem. Configure the terminal to the maximum baud rate the modem can handle (for example for a 9600 baud modem set the terminal to 9600 baud).

Use straight thru cable (pin 1 to 1, 2 to 2, 3 to 3, etc).

AT&F {set factory defaults}
AT&C1 {tracks presence of carrier}
AT&S1 {tracks presence of DSR}
AT&D2 {normal function of DTR when line drops}
ATS0=1 {set auto answer to one ring}
AT&Q0 {asynchronous mode} (9600 baud only)
AT&K0 {local flow-control disabled}
ATQ1 {modem doesn't return result codes}
ATE0 {disable character echo in command state}
AT&W0 {save parameters in user profile 0
AT&V {display all settings}

MODEM CABLING:

Next disconnect the terminal and connect the modem to your DTC using an HP 40233A cable. The cabling pinout is not a symmetrical cable.

DTC [Computer] [Data Set] Modem
DTC SIDE MODEM SIDE
(LABELED "COMPUTER") (LABELED "DATA SET")
25 PIN MALE 25 PIN MALE

1 ------------------------------- 1
2 <------------------------------ 3
3 ------------------------------> 2
4 <------------------------------ 8
6 ------------------------------> 20
7 <-----------------------------> 7
8 ------------------------------> 4
9 <------------------------------ 22
20 <------------------------------ 6
22 <------------------------------ 5
King is the customer!
Honored Contributor

Re: best dial back modem

Uh, if you have an older cable, one that has pin 23, be sure to get a wire cutters and *clip* that pin short. It will improve the reliability of the connection. (Hey! don't look quizically at me, HP recommended this fix)
//Add this to "OnDomLoad" event