UBI EasyCoder 501 Service Manual page 138

UBI EasyCoder 501 – Service Manual
18. "UART1:", cont'd.
18.3
RS 422
RS 422 is a point-to-point interface for connection between one
printer and one host computer over a distance of up to 1,200 metres
(4,000 ft.) by use of a four-wire cable. The transmission is full
duplex, i.e. reception and transmission can take place simultane-
ously.
+ RS422 IN
- RS422 IN
+ RS422 OUT
- RS422 OUT
RS 422 connection between host computer and printer.
RS 422 requires an additional circuit and a number of straps to be
fitted on the CPU board:
- +
P203
P-203
(external +5V)
P202
P208
232
P206
CL
P209
P207 422
P204
IC-207
P205
IC-207
(RS 422 circuit)
P-202
(interface select)
P-204 – P-209
(comm. straps)
Continued!
138