IBM 7220, Instruction Manual

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Cable Diagrams
Appendix
D
D-1
D.1 RS232 Cable Diagrams
Users who choose to use the RS232 interface to connect the model 7220 lock-in
amplifier to a standard serial port on a computer, will need to use one of two types of
cable. The only difference between them is the number of pins used on the connector
which goes to the computer. One has 9 pins and the other 25; both are null modem
(also called modem eliminator) cables in that some of the pins are cross-connected.
Users with reasonable practical skills can easily assemble the required cables from
parts which are widely available through computer stores and electronics components
suppliers. The required interconnections are given in figures D-1 and D-2.
Figure D-1, Interconnecting RS232 Cable Wiring Diagram