unhd (Roger Gonzalez ) (10/29/90)
This is intended for the novice cable builder I built my cable out of various stuff I "borrowed" from work: 3 female connector pins from DB-25 kit heat shrink jack for modular 6 pin version of phone jack modular cable db25 connector with same 6-pin jack on back The loose female db25 pins fit perfectly on the calculator jack. These cables and jacks are what my lab (and the university) uses for connecting terminals to the terminal server jacks on the wall. ____ ___| |___ | | The middle 4 wires are the only really important ones. | | Of these, only 3 are required. |_!!!!!!_| I just scoped out what my 'pc was expecting on the cable, keeping in mind that db25 2 and 3 are tx/rx and 7 is signal ground. Find transmit by getting into a terminal emulator and typing characters. Receive can be found by attempting loopback. When you get characters back on the screen, you have found receive. Signal ground is easy. I got that by doing a continuity check from pin 7 on the db25 through the modular cable, to the remaining two middle wires. Et voila. Connect signal ground to signal ground, receive from the calculator to transmit from the pc, and vice versa. You have a rude and crude cable. (You did heatshrink the connections, right?) The nice thing about this cable is that I can easily swap db25 plugs to fit the needs of different machines. I'm going to take off the heat shrink and cast a real plug with this quick dry epoxy stuff we have. It makes a nice rubberlike connector. Of course, you can also go directly to a db25 or db9 connector. But, I worked with (stole) the materials immediately at hand. So, where's all them ftp sites at? I want a terminal emulator for the 48! -Roger -- "The question of whether a computer can think is no more interesting than the question of whether a submarine can swim" - Edsgar W. Dijkstra rg@unhd.unh.edu | UNH Marine Systems Engineering Laboratory r_gonzalez@unhh.bitnet | Durham, NH 03824-3525