topic Re: I'm still trying to make a modem to work in Operating System - HP-UX

I'm still trying to make a modem to work

Jun Zhang_4 — Thu, 11 Mar 2004 18:08:28 GMT

The RJ45 jack on PCI Mux port module need 10 pin cable, I have only 8 pin cables. To convert to DB25 connector on modem, I missed the Data Set Ready line, which is RJ45 pin 10 to DB25 pin 6, compared to the HP suggested pinouts.
Will this hinder a modem from working?

Jun

Re: I'm still trying to make a modem to work

A. Clay Stephenson — Thu, 11 Mar 2004 18:50:12 GMT

There is no other answer than "it depends". Is this an incoming, outgoing, or bidirectional modem? Do you want full hardware handshake so that full 8-bit data transmission can be used? The DSR line is used as a STATUS line. Man 7 modem; it fully explains how the function of these lines.

The only thing I can tell you for sure is that I use the 10-pin connectors and sense DSR and my modems work perfectly.

Re: I'm still trying to make a modem to work

A. Clay Stephenson — Thu, 11 Mar 2004 19:10:24 GMT

I suppose the thing that has always bugged me about the HP 10-pin RJ-45's is that they use two pins for SIGNAL GROUND instead of only one pin for SIGNAL GROUND and using the other for DSR. That would have left only Pin 1 and Ring Indicator which nobody uses. I could have understood using two pins for ground if one were SIGNAL and the other were CHASSIS.

By the way, I have found a non-HP source for 10-pin RJ-45 plugs. www.digikey.com Part No. A9129-ND.

Re: I'm still trying to make a modem to work

Jun Zhang_4 — Fri, 12 Mar 2004 09:20:20 GMT

Do you mean a third pin other than the two signal grounds by "the other", or one of the two signal grounds?
The thing is that you'll not be able to change the RJ45 jacks on the port module. I see what you mean, though -- HP shouldn't use 10, if 8 is enough -- I couldn't agree more.

Jun