
9XTend? ? OEM ? RF ? Module ?‐? Product ? Manual ? v2.x4x ? [2007.01.04]
Appendix ? B: ? Development ? Guide
RS-485 (2-wire) Operation
When operating within the RS-485 protocols, all communications are half-duplex.
DIP Switch Settings and Serial Port Connections
Figure ? B ‐ 16.
RS ‐ 485 ? (2 ‐ wire) ? Half ‐ duplex ?
DIP ? Switch ? Settings
Figure ? B ‐ 17.
Pins ? used ? on ? the ? female ? RS ‐ 232 ? (DB ‐ 9) ?
Serial ? Connector ?
Figure ? B ‐ 18.
RS ‐ 485 ? (2 ‐ wire) ? w/ ? Termination ? (optional)
Termination ? is ? the ? 120 ? Ω ? resistor ? between ? T+ ? and ? T ‐ .
DIP ? Switch ? settings ? are ? read ? and ? applied ? only ? while ? powering ‐ on.
Note: Refer to Figures B-09 and B-10 for RJ-45 connector pin designations used in
RS-485/422 environments.
Table ? B ‐ 05. RS ‐ 485 ? (2 ‐ wire ? half ‐ duplex) ? signals ? and ? their ? implementations ? on ? the ? XTend ? Module ? Assembly
DB-9 Pin
2
5
8
9
1, 3, 4, 6, 7
RS-485 Name
T/R- (TRA)
GND
T/R+ (TRB)
PWR
Description
Negative Data Line
Ground Signal
Positive Data Line
Power
Implementation
Transmit serial data to and from the XTend Module Assembly
Ground
Transmit serial data to and from the XTend Module Assembly
Optional power input that is connected internally
to the front power connector
not used
Wiring Diagram
Figure ? B ‐ 19. ?? XTend ? Module ? Assembly ? in ? an ? RS ‐ 485 ? (2 ‐ wire) ? half ‐ duplex ? environment
? ? 2007 ? MaxStream, ? Inc.
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