twin RS232 - a two-into-one or one-into-two RS 232 link

a two-into-one or one-into-two RS 232 link The D-type connectors generally used for RS 232 interfaces are quite robust and are well able to take the wear and tear that comes with fre- quently being inserted and removed. The human computer user can, however, get a bit frayed around the edges when he has to change his computer"s RS 232 lead from one peripheral to another for the ump- teenth time. This is not helped by the fact that, for aesthetic reasons, the RS 232 port is almost invariably located out of sight at the back of the computer. Fortunately, many people never have this problem but none the less it does crop up fairly often: such as when a computer, ter- minal, and printer are used together, or one computer and two printers, or two computers and one printer. In answer to an unspoken plea for a cure for this situation we have designed what is, in effect, an RS 232 single-pole two-way switch. The interesting part of the circuit is the two high-efficiency LEDs con- nected to...