Null-Modem Cable Schematics --------------------------- To transfer data/prg/etc... , one can make use of the null-modem cable. With this you don't need any modem also. Only thing has to be done is,plugging this cable to the computers (just two computers, one to many communication with this kind of schematics causes data collision). After plugging, and loading terminal programs to the computers, just send the program, from one of the machine and receive it using the other one. . You can use Novaterm9.5 at C64 side and Lynx at the IBM side for example. . You have to use same transfer protocol at both sides (eg. xmodem ) . If you want you can put one of the terminal programs into BBS mode. The Schematics: --------------- 1.) DB-25 to DB-25 Null-Modem cable. db-25 db-25 Parts List ----- ----- ---------- tx 2-----------3 rx . Two DB-25 male connector. rx 3-----------2 tx . 1-2 meter of 5(or 3) line shielded wire. rts 4-----------5 cts * cts 5-----------4 rts * * If you want, you don't use rts/cts lines. gnd 7-----------7 gnd 2.) DB-9 to DB-25 Null-Modem cable. db-9 db-25 Parts List ----- ----- ---------- rx 2-----------2 tx . One DB-25, one DB-9 male connector. tx 3-----------3 rx . 1-2 meter shielded wire with 5 or 3 lines. gnd 5-----------7 gnd cts 7-----------4 rts * * It is OK if not to use these lines. rts 8-----------5 cts * 3.) DB-9 to DB-9 Null-Modem cable. db-9 db-9 Parts List ----- ----- ---------- rx 2-----------3 tx . Two DB-9 male connector. tx 3-----------2 rx . 1-2 meter of 3(or 5) line shielded wire. gnd 5-----------5 gnd cts 7-----------8 rts * * Not using these lines does not cause a rts 8-----------7 cts * problem at low speeds. Term. progs. can use XON/XOFF bytes for data flow control. The DB-25 Connector. (looking at back) The DB-9 Connector. 13 12 ..... 3 2 1 5 4 3 2 1 ------- -------- ------------- \ o o o ... o o o / \ o o o o o / \ o o ... o o / \ o o o o / ---- ..... ----- --------- 25 14 9 8 7 6 Ilker Ficicilar filker@newton.physics.metu.edu.tr e068214@narwhal.cc.metu.edu.tr ---