Contec BX-100n-DC5000-C01, User Manual, Page: 41 / 145

4. Each Component Function
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BX-100n User’s manual
Table 4.8. RS-422/485 Port Connector (Inside the RAS Connector)
Pin No. Signal name Meaning
2
TX + Transmitted data +
10
TX - Transmitted data -
3
RX + Received data +
11
RX - Received data -
Reference
For more information on the RAS connector see Table 4.12, "RAS connector".
RS-422/RS-485 Specifications
- Transmission
method : RS-422/RS-485-compliant, asynchronous, serial transmission, half
duplex/full duplex
- Baud rate : 50 - 115,200bps (programmable)
- Signal extension distance : 1.2km Max.
Terminal Resister when RS-485 is in Use
It is set in BIOS setup menu. At the time of shipment, the setting is “no terminating resistance”.
For more details on this, please refer to Chapter 5, “Onboard Device”.
Control of Transmitted Data in Half-Duplex Mode
In half-duplex mode, the transmission buffer needs to be controlled in order to prevent collision of
transmitted data. The BOX-PC uses RTS and controls the buffer with modem control register's bit 1.
Transmission and reception gate control by the register setting of port address 4007h is allowed only for
the RS-422/485 (Serial port D). For more information see section, "General-purpose I/O and Remote
Reset" in Chapter 4.
Modem control register
(Set I/O a4H) bit 1 : 0 … RTS is High. (Disable transmission)
1 … RTS is Low. (Enable transmission)