RCA COSMAC Operator's Manual page 73

APPENDIX A
TELETYPE HALF-TO-FULL DUPLEX CONVERSION INSTRUCTIONS
For a Teletype connected for I~LF DUPLEX operation. the
following modifications can be made to convert it to FULL
DUPLEX.
1.
2 •
Locate a black terminal strip in the back. (see Fig.20 below)
Move the BROWN/YELLOW. and WHITE/BLUE wires from pins
3 or 4 to pin S.
For Teletypes connected for 60
rnA
operation. the following
modifications can be made.
1. Move the VIOLET wire from pin 8 to pin 9.
2. Move the BLUE wire connected to the current source
resistor (a flat green resistor with 4 tabs located
to the right of the keyboard) from the 7S0n tab to the
l4S0n tab.
Figure 21 below is also included for the reader's inform-
ation. It illustrates all of the interface circuitry. between
Microkit logic signals and I/O typewriter pins -- for the
FULL DUPLEX mode. Notice particularly the isolation of the
two Teletype (TTY) current loops.
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