
5 Hardware
PCS-9785 Satellite-Synchronized Clock
5-14
Date: 2014-10-15
NR1218A
Figure 5.6-5 COM Module (NR1218A)
The correct serial port wiring is shown in the following figure. Generally, a foiled cable with at least
two pairs of twisted pairs shall be applied. One pair of the twisted pairs are respectively used to
connect the transmission and reception terminals. The other pair of twisted pairs is used to
connect the signal reference "SGND" of the communication interface. If there is a free terminal or
a grounding terminal "FGND" for all the communication ports, it is suggested to connect the foiled
layer of the cable when connecting multiple devices in series. The foiled layer connection of the
cable shall be grounded at only one end.
01
02
03
RxD
TxD
SGND
RS
-232
FGND 04
Twisted-pair wire
To the foiled layer of other
cable with single point earthing
Figure 5.6-6 Serial port wiring of NR1218A
Table 5.6-8 Pin definition of NR1218A
Pin No.
Symbol
Description
Port No.
01
1 RXD
RS-232: RXD
Serial port 1
02
1 TXD
RS-232: TXD
03
1/2 SGND
Signal reference
04
1/2 FGND
Foiled layer
05
2 RXD
RS-232: RXD
Serial port 2
08020
08020
08020
08020
08020
08020
08020
08020
08020