Andrew Rodland writes ... > > I tried to build myself a PC-to GS null modem cable from Radio shack, but > radio shack and everything I could find around here didn't have mac > cables. > I now want to build my own. can anyone give me the pin connections for all > of these wired together? instead of > DIN-8 -> DB-25 -> null modem adaptor -> DB-25 - DB-9 convertor > I just want the pinout for 8-pin mini-din to DB-9 serial > with null modeming > and hardware handshaking. If anyone can figure out what I'm trying to say > here, could you please try to do this for me, as I have almost given up. The easiest way to make a NULL modem cable for a IIgs is to buy a standard IIgs/Mac high-speed modem cable and stick a NULL modem adaptor on the end. Here are details for a IIgs high-speed modem cable: View is looking into the cable connector/plug at the pins. Male Mini-Din 8 RS-232 Male Dsub-25 6 7 8 01 02 03 04 05 06 07 08 09 10 11 12 13 3 4 5 14 15 16 17 18 19 20 21 22 23 24 25 1 2 DIN-8 Dsub-25M Signal Discription 3 2 TD (Transmit Data) 5 3 RD (Receive Data) 4,8 7 GND (Ground) 2 5 CTS (Clear to Send) 1 4,20 RTS & DTR (Ready to Send and Data Term Ready) 7 8 DCD (Data Carrier Dectect) You can buy a IIgs high-speed modem cable from Intrec, MC Price Breakers, ThinkStuff, and other places. Evidently, it is the same as a Mac 8-pin mini-din --> 25-pin Dsub cable; so, Mac stores should offer the cable. InTrec Software (888-PROTERM; http://www.intrec.com ) sells ProTerm A2 and high-speed GS modem cable; the "InTrec Store" sells used Apple II/IIgs computers, peripheral hardware, and software at good prices MC Price Breakers (360-837-3042; http://www.mcpb.com ) sells memory boards, high-speed GS modem cables, and other Apple II hardware ThinkStuff ( http://www.thinkstuff.com/main.htm ) sells Mac/IIgs hi-speed modem and NULL modem cables. A typical NULL modem adaptor is two Dsub 25-pin female sockets (call them "A" and "B") wired back-to-back as follows ... Socket-A Socket-B 1 -> 1 2 -> 3 3 -> 2 4 & 5 -> 8 6 & 22 -> 20 7 -> 7 8 -> 4 & 5 20 -> 6 & 22 A Dsub-25 female connector viewed from the front ,----------------------------------------. \ 13 12 11 10 09 08 07 06 05 04 03 02 01 / \ 25 24 23 22 21 20 19 18 17 16 15 14 / `------------------------------------' If you can find a couple old-style Dsub-25 plug casings, the sockets can be mounted and the casings can be glue-gunned together to make a nice compact unit. For Apple2-PC (or Mac, etc.) transfers, you plug the modem cable from the Apple II into one side of the NULL modem and the modem cable from the PC into the other side. If the PC has a 9-pin serial port connector, use a 9-to-25 adaptor cable to connect to the NULL modem. Similarly,for Mac users, if the Mac cable has a special connector, use a converter to a male Dsub-25M connector for plugging into the NULL modem. A good reason for having a NULL modem adaptor using standard 25-pin Dsub connectors is that it can be used for connecting nearly any two computers. To connect to the PC, you can plug in a modem cable which ends with a standard 25-pin male Dsub connector. If your PC cable ends with a 9-pin plug, you can use a 9-->25 adaptor. (ThinkStuff sells several NULL modem adaptor cables. See http://www.thinkstuff.com/catalog/1/9/30.htm . NULL modem adaptors are a fairly common item from surplus parts sellers like All Electronics, MECI, MPJA, ...) All Electronics (800-826-5432; http://www.allcorp.com ) major surplus and new parts seller- switches, LCD panels, connectors, transformers, caps, IIgs-type lithium batteries, etc. MECI (800-344-6324; http://www.meci.com ) surplus electronic parts- fans, tubes, solenoids, IC sockets, 50-25 SCSI cables and adaptors, ... MPJA/ Marlin P. Jones (800-652-6733; http://www.mpja.com ) many power supplies, NULL modem, Parallax BASIC stamp, misc kits, LED displays, LCD panels, ... Rubywand