Functional Description
CPB902
C P B 9 0 2 U s e r M a n u a l
53
© 2 0 0 8 F a s t w e l v . 1 . 5 b E
Table 4.16:
Serial Ports Pin Assignments
COM2
COM1
COM3/COM4/COM5/COM6
Pin #
RS-232
RS-232
RS-232
RS-422
RS-485
1
DCD
–
DCD
TX+
D+
2
DSR
–
DSR
TX-
D-
3
RXD
RXD
RXD
–
–
4
RTS
–
RTS
–
–
5
TXD
TXD
TXD
–
–
6
CTS
–
CTS
–
–
7
DTR
–
DTR
RX+
–
8
RI
–
RI
RX-
–
9
GND
GND
GND
GND
GND
10
–
–
+5V
+5V
+5V
COM2, COM3 – COM6 ports have ESD and overload protection. COM1 port has no protection.
Physical protocols for COM3-COM6 ports are switched by software. Jumpers on J6 (COM3),
J8 (COM4), J10 (COM5) and J12 (COM6) pinpads connect terminators to RS-485/RS-422 signal
lines. In RS-232 mode the terminators should not be connected. The pins of all pinpads have
identical designation shown in the following figure.
Figure 4.19:
COM3 – COM6 Ports Jumpers
1
2
3
4
RX-/RX+ T erminator Enabled
TX-/T X+ T erminator Enabled
To use any of the COM3 – COM6 ports in RS-422 or RS-485 mode, do the following:
§
Set jumpers on the pinpad, corresponding to the port;
§
Initialize the port by software
The figures 4.20 and 4.21 show the RS-422 and RS-485 interfaces structure respectively.
Figure 4.20 shows two modules connected in RS-422 mode. The jumper connecting terminator is
set on receive lines only (lines RX+ and RX-). In RS-485 mode the terminators are connected only
on devices at the ends of the line (see Figure 4.21). Resistance of terminators is 120 Ohm. The
complete description of jumpers can be found in