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connectors. Those making their own cable should use the standard 25-way D-type connectors and make the following connections:

The connection for the computer to receive data is only required if the printer also has a keyboard for data input.

2.2 Serial printers with handshake

These printers require the additional ‘handshake’ line to be connected in order that the printer can notify the computer when printing is to be suspended pending emptying of the printer memory. Normally your dealer will supply suitable connectors and cables, but if you wish to make up your own you should follow the instructions below.

The printer handshake may be either at a 5 volt TTL level, in the case of the Nascom Imp printer, or may be at 12 volt RS232 levels. The connections to be made should be exactly as described for the serial printer without handshake but with the following additional connection.

Pin 8 of PL2 must be connected to TP3 on the main beard. (Standard on all recent production Nascom 2’ and 3’s).

The handshake signal input must be limited to 5 volt TTL levels, which is done as follows: (this connection is standard all on current Nascom 3’s)

Connect pin 20 of the D-type socket in the computer to a 1K ohm resistor, the other end of the resistor being connected to the junction of 2 diodes (eg 1N4001). One of these diodes is connected to the ground pin (7) and the other to the grey lead from pin 8 of PL2; in both cases the cathode of the diode (the end marked with a ring in most cases) is connected to the common junction.

2.3 Parallel printer connections

Once again your dealer should he able to supply suitable cables and connectors, which will be made up according to the data given below for those assembling their own connections.