chan@chansw.UUCP (Jerry H. Chan) (03/19/90)
In article <8891@boring.cwi.nl>, leendert@piring.cwi.nl (Leendert van Doorn) writes: > This worked partially, a getty was spawned and read the input for a login > name. When I typed my name followed by a cariage return, it executed login > which immediatly exited. Login was executed (I know, because he asked me I ran into the same problem using a COM: port on my system; the fix was to make sure that CD was tied high on the host side, assuming that your COM: port hardware really looks at that signal (I have seen hardware which doesn't have traces on the com board to the DB25 connectors for CD). This was the case for the version of getty / uugetty shipped with ISC 2.0.2; I don't know if this is a *bug* or a feature :-). [I will generalize the pinout's for connecting terminals to hosts so that other readers might benefit.] If I recall properly (assuming DB25 connectors on each side), here are the starting pinouts for a typical cable between the host and the terminal: Host Terminal Notes --------------- --------------- ----------------- 1 (Chassis Gnd) <-> 1 (Chassis Gnd) Will work without 2 (Xmt Data) -> 3 (Rcv Data) 3 (Rcv Data) <- 2 (Xmt Data) 7 (Sig.Gnd) <-> 7 (Sig.Gnd) The last three lines might look one of two ways, depending on whether your terminal uses DTR or RTS/CTS flow control, the difference being in the signal used for flow control -- PAY SPECIAL ATTENTION TO THE CD (8) SIGNAL ON THE HOST SIDE: [Note: ISC does not currently support HW flow control for the COM: ports; I believe that the FASY drivers do ???] XON/XOFF FLOW CONTROL: Terminal / Host handshake using ^S / ^Q; you can get away with putting a jumper between pins 20 (DTR) & 8 (CD) on the host side assuming that your DTR line is asserted high when the port is open (as should be the case): Host Terminal Notes --------------- --------------- ----------------- 8 (CD) <--\ Loopback 20 (DTR) <--/ Loopback DTR FLOW CONTROL: Terminal raises DTR when ready for more data from the host, inverts when the terminal wants to host to stop. There is a signal on the terminal which is forced HIGH as long as the terminal is powered on -- I've assumed that it is pin 4 (RTS) on the terminal here -- Host Terminal Notes --------------- --------------- ----------------- 8 (CD) <- 4 (RTS) If RTS is HIGH 4 (RTS) -> 5 (CTS) 5 (CTS) <- 20 (DTR) Flow control here RTS/CTS FLOW CONTROL: Identical to DTR flow control, except that the RTS (4) and DTR (20) lines are swapped on the terminal side -- Host Terminal Notes --------------- --------------- ----------------- 8 (CD) <- 20 (DTR) If DTR is HIGH 4 (RTS) -> 5 (CTS) 5 (CTS) <- 4 (RTS) Flow control here Refer to your manual for info regarding the type of flow control used by your terminal. Also recommended is a good, cheap break-out box so that you can see which signals are actually used by your host / terminals. Hope this helps. -- Jerry Chan 508-853-0747, Fax 508-853-2262 |"My views necessarily reflect the Chan Smart!Ware Computer Services & Prods | views of the Company because Worcester, MA 01606 | I *am* the Company." :-) {bu.edu,husc6}!m2c!chansw!chan \---------------------------------