Jumper Setting; Rs-232C/422/485 Selector: Jp1/Jp8 - Contec SPC-8450-LVA User Manual

4. Jumper Setting

RS-232C/422/485 Selector: JP1/JP8

Table 4.1. RS-232C/422/485 Selector(JP1/JP8)
23 21 19 17 15 13 11 9 7 5 3 1
RS-232C
(Default)
25 22 20 18 16 14 12 1 0 8 6 4 2
23 21 19 17 15 13 11 9 7 5 3 1
RS-422
25 22 20 18 16 14 12 1 0 8 6 4 2
23 21 19 17 15 13 11 9 7 5 3 1
RS-485
25 22 20 18 16 14 12 1 0 8 6 4 2
1. For RS-485, TX+(pin 2) and RX+ (pin 3) must jumper together
inside the D type connector.
2. TX- (pin 1) and RX- (pin 4) is the same.
Transmit date control in half-duplex mode
In half-duplex mode, the transmission buffer must be controlled to prevent transmit data from causing a
collision. The SPI-8450-LLVA uses the RTS signal and bit 1 in the modem control register to control
transmit data.
Modem control register
(Setting I/O address +4H) bit 1:
Setting the RS-422/RS-485 receiver disable control jumper
When the RS-422/RS-485 port is used, the RTS signal is used for driver enable control Connecting JP2
Pins 4 and 6 set to OFF disable the receiver at the same time, preventing the port from receiving output
data to an external device.
SPC-8450-LVA
JP1
9 7 5 3 1
10 8 6 4 2
JP1
9 7 5 3 1
10 8 6 4 2
JP1
9 7 5 3 1
10 8 6 4 2
0 ... RTS High (Disables transmission)
1 ... RTS low (Enables transmission)
JP8
JP8
JP8
4. Jumper Setting
25