Rs422 Port A And Rs422 B; Rs422 Port A - Micros Systems Workstation 4 LX Service Manual

RS422 Port A and RS422 B

The WS4 features a pair of multi-purpose RS422/232 ports utilizing 8-Pin modular
connectors called RS422-A and RS422-B. Each port is identical to the Eclipse
IDN/LCC port. Pin-outs for the RS422 and RS232 sections of each port can be found
in Appendix B.
RS422 Port A (REF: AB28/ABRD36 - Sheet 16)
UART1 in the Super IO chip U15, is dedicated to the RS422 Port A. Several GPIO
lines are dedicated to the control signals used by this port. It is assigned to COM4 and
the default setting of RS422(+) designates the port as the 'sender' of data where it is
used by applications such as 3700 or 9700 to drive printers with IDN modules
installed.
The Table below summarizes the transmit, receive, and control signals for RS422 Port
A.
SIgnal Name
TXD4
422_232_SEL_4
422_MODE_4
TRANSMIT_EN4
DE_4A
DE_4B
RE_4A
RE_4B
RXD4_232
Workstation 4 and 4 LX Field Service Guide
Type
O Contains serial data to be transmitted over
the RS422 (U9-4, U10-4) or RS232 (U7-16)
interface. Always enabled.
O When Low (0), RS422-A interface is active.
When High (1), RS232-A Interface is active.
O When High (1), RS422-A is (+) Mode (IDN).
When Low (0), RS422-A is (-) Mode (LCC).
O Used with 422_MODE_4 to generate DE_4A,
DE_4B, RE_4A, and RE_4B for controlling
RS422 Transceivers U9 and U10.
O Transmit Enable at U9-3 for RS422-A IDN
mode. Produced by ANDing TRANSMIT_EN4
with 422_MODE_4 at U14-8.
O Transmit Enable at U10-3 for RS422-A LCC
mode. Produced by ANDing TRANSMIT_EN4
with 422_MODE_4# at U14-3.
O Receive Enable at U9-2 for RS422-A IDN
mode. From 422_MODE_4.
O Receive Enable for U10-2 for RS422-A LCC
mode. Produced by inverting 422_MODE_4 at
U27-6.
I Contains serial data received from the RS232
Interface. Produced by ANDing RXD4_232#
with inverted 422_232_SEL_4 at U14-11.
WS4 Technical Overview

RS422 Port A and RS422 B

Description
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