PDT-11/150 down

A few things I'll add to that list : A 'universal RS232 ribbon cable'. I've never seen these for sale, you have to make them. It's a length of 25 way IDC cable with a DB25 plug and a DB25 socket crimped on at each end (4 conenctors total). It gets round gender problems, and it's also useful for linking my Tekky datacoms analyser to a line (this has a single DB25 socket on the back) I made up 2 different null-modem adapters. The fist one is labelled 'full handshake' and has the following connections : 1 (PG)---------------1 (PG) 2 (TxD) ------------ 3 (RxD) 3 (RxD) -------------2 (TxD) 4 (RTS)--------------5 (CTS) 5 (CTS) -------------4 (RTS) 6 (DSR)---+----------20 (DTR) 8 (DCD)---+ 7 (SG)---------------7 (SG) 20 (DTR) --------+---6 (DSR) +---8 (DCD) The other is labelled 'loopback handshake) and has these connections 1 (PG)---------------1 (PG) 2 (TxD)--------------3 (RxD) 3 (RxD)--------------2 (TxD) 4 (RTS)---+ +---4 (RTS) 5 (CTS----+ +---5 (CTS) 7 (SG)---------------7 (SG) 6 (DSR)---+ +---6 (DSR) 8 (DCD)---+ +---8 (DCD) 20 (DTR)--+ +---20 (DTR) The first is used when both ends make sensible use of the handshake lines, the second when the don't ( and you rely on software handshaking). I had to make up both of these myself, the null-modem adapter I bought ready made had a _crazy_ set of internal connections (I think 4 and 5 at each side were linked and linked to 4 and 5 at the other end). And for some reason the purchased one had a plug on one end and a socket on the other (mine home-made ones are sockets at both ends). -tony