Contec SPC-8520-LA - RS-232 C;422 A;485 Selector: JP2;JP3

4. Jumper Setting
30
SPC-8520-LA , SPC-8521-LA
RS-232C/422A/485 Selector: JP2/JP3
Table 4.2. RS-232/422A/485 Selector
RS-232C
RS-422A
RS-485
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.
(Default)
JP3
19 17 15 13 11 9 7 5 3 123 21
20 18 16 14 12
10 8 6 4 225 22
JP3
19 17 15 13 11 9 7 5 3 123 21
20 18 16 14 12
10 8 6 4 225 22
JP3
19 17 15 13 11 9 7 5 3 123 21
20 18 16 14 12
10 8 6 4 225 22
JP2
JP2
JP2
9
7531
10
8642
97531
10
864
2
9
75
31
10
864
2
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 product 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: 0 … RTS High (Disables transmission)
1 … RTS low (Enables transmission)