See below ...
Joe.
> -----Original Message-----
> From: Michael Polak [SMTP:[EMAIL PROTECTED]]
> Sent: Wednesday, 21 February 2001 10:34
> To: [EMAIL PROTECTED]
> Subject: Re: problems connection HP-LX palmtop to /dev/ttyS0 in Linux
> ...
>
> Gregory J. Feig wrote:
>
> > On Mon, 19 Feb 2001 13:20:10 +0100, Michael Polak wrote:
> >
> > ---------snip------
> >
> >
> >
> >> Laplink is probably crossed cable:
> >
> >
> >> ______ _____
> >> PC \/ PC
> >> ______/\_____
> >
> >
> > YES...Laplink for Serial Connection IS crossed cable (must be, just
> > think about it....<g g g>)
>
> Yes, this is what I did (thought about it), and though it
> should work. I just wonder why I was not able to connect
> from one terminal to another,using HP-LX <-> PC serial cable
> (NULL modem, obviously). Both parties were connected using 9600
> bps, and connection physicaly obviously works (interlnk/intersvr
> in DOS...)
>
> >> Now, is the same cable used to connect modems to PC ?
> >
> >
> > NO...PC to Modem is "straight" cable....it was originally designed
> > that way.
>
> I was thinking this too.
>
> >> If no, my second cable would probably have to be crossed
> >> again, because cell phone is designed to behave the same
> >> way as modem, so the cable will be probably also the same...
> >
> >
> > YES....cell phone is designed to look (from the PC) like a modem
> > connected there.
>
> Yes, so if I want to extend null-modem cable (HP-LX <->
> Cannon 9pin) by adapter to connect to cell phone, I need
> another null-modem-like crossed cable, Cannon <-> cell phones
> (cell phones are unfortunately too small to be shipped with
> serial Cannon connectors ... or maybe manufacturers don't
> want them to be that much compatible... :-(
>
[da Silva, Joe]
Yes, you need another null-modem cable, so you have :
1. HP-LX <-> DE9 null-modem cable
2. DE9 <-> DE9 null-modem cable
3. DE9 <-> cell phone (straight) cable
(Note: DE9 connectors are often WRONGLY called
DB9 - however, the second letter indicates shell size,
and you all know what a "B" shell size is, right? ;-)
Note three things :
1. There is no "standard" null-modem cable. Some cross
all hand-shaking signals, some just loop them back.
2. Many cell-phones have TTL signals and use a converter
circuit within the cable to produce/receive RS-232 signals.
3. Not sure if your cell phone provides a Carrier Detect
signal ... some do not ... does your software (eg. PPP
packet driver) require this ... ?
>
> > If you have an Internal Modem (as you said you did in previous post)
> > ...then you need to go out to a Serial Port to connect to the cell
> > phone - treating the cell phone as if it was a modem - and this
> > will probably mean that you will need to disable/remove the Internal
> > Modem before you can do that.
>
> There is no internal modem in HP-LX - HP-LX is tiny palmtop.
> I have got internal modem in my DOS box dedicated to
> Arachne development....
