Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcso!hpldola!hp-lsd!was
From: was@hp-lsd.COS.HP.COM (Bill Stubblebine)
Newsgroups: comp.sys.apple
Subject: Re: Modem for Laser 128EX
Message-ID: <7610003@hp-lsd.COS.HP.COM>
Date: 17 Feb 90 03:58:01 GMT
References: <17711@eerie.acsu.Buffalo.EDU>
Organization: HP Logic Systems Division - ColoSpgs, CO
Lines: 53

/ hp-lsd:comp.sys.apple / diachun@acsu.buffalo.edu (justin d diachun)

> I own a Laser 128EX Apple compatible computer, and I want to buy a 2400
> baud modem for it.  The cheapest and most reliable external modems seem
> to be for the IBM, so I was going to buy one, but I will need an adaptor
> cable to plug in to my built in serial port.

	Boy, now we've really arrived ...  "PC compatible" external
	modems.  Sheesh!

> My question is, what kind of adaptor cable will I need?  Where can I get
> one?  The serial port on my machine is sort of round, and claims to be
> an "RS-232C" port.  Is this the same kind as is used by an Apple //c?
> Can I use an Apple //c to RS232 cable for this?

	The "sort of round" connector is called a 5-pin DIN connector,
	the other end is a 25-pin male "D" type connector used on most
	external modems, even the PC-compatible ones.  (Can't help
	smiling.)  Either connector can be bought for ~ $1.50 at Radio
	Shack.  An entire cable, including a hank of 5 conductor wire
	should cost you less than $5.00 to build.

	The connections for the serial cable between a Laser 128 (or
	Apple //c) with a Hayes compatible (i.e., RS-232) modem are
	shown below.  Picture the DIN connector as a half circle
	looking either at the female (Laser back panel) connector, or
	looking at the wiring side of the male plug.

           5-pin DIN                       PIN-OUTS
           Connector               DIN   RS232   FUNCTION
           ---------               ---   -----   --------
                                    1  -  20     DTR (Data Terminal Ready)
         5           1              2  -   2     Transmit Data (from Laser)
           4       2                3  -   7     Ground
               3                    4  -   3     Receive Data (to Laser)
                                    5  -   6     DSR (Data Set Ready)

	Although I didn't need to for my Hayes 1200, you may find that
	you need to jumper pins pins 4-5 (RTS/CTS) on the 25 pin
	(modem) end to keep the modem happy.

> Any help is greatly appreciated.  Thanks in advance.

	You're welcome.

> Justin Diachun

                                Bill Stubblebine
                                Hewlett-Packard Logic Systems Div.
                                8245 N. Union Blvd.
                                Colorado Springs, CO  80920
                                was@hp-lsd.hp.com  (Internet)
                                (719) 590-5568