GE AquaTrans AT868, Abridged Manual

Page: 19 / 67

Installation 1-11
September 2004
Wiring the Serial Port
The AT868 is equipped with a built-in serial communications port.
The standard port is an RS232 interface, but an optional RS485
interface is available upon request. Proceed to the appropriate section
for wiring instructions.
Wiring an RS232 Interface
Use the serial port to connect the AT868 to a printer, an ANSI
terminal or a personal computer. The RS232 interface is wired as
Data Terminal Equipment (DTE), and the signals available at the
COMMUNICATION terminal block are shown in Table 1-2 below.
To wire the RS232 output, complete the following steps:
1.
Use the information in Table 1-2 below to construct a suitable
cable for connecting the AT868 to the external device. If desired,
an appropriate cable may be purchased from GE.
Note: Signal names that imply direction (e.g., transmit and receive)
are named from the point of view of the DTE device (the GE
meter is usually considered the DTE device). When the RS232
standard is strictly followed, these signals are labeled with the
same name and pin # on the DCE device side. Unfortunately,
the convention is not followed because the DTE and DCE side
get confused. Therefore, connections that imply direction are
changed to reflect their direction on the DCE side.
Table 1-2: RS232 Connection to DCE or DTE Device
COMMUNICATION
TB
Colors for
GE Cable
(flying leads)*
Signal
Description
DCE
DB25
Pin #
DCE
DB9
Pin #
DTE
DB25
Pin #
DTE
DB9
Pin #
5 White DTR (Data
Terminal Ready)
20 4 20 4
4 Yellow CTS
(Clear to Send)
4 7 5 8
3 Green COM (Ground) 7 5 7 5
2 Red RX (Receive) 2 3 3 2
1 Black TX (Transmit) 3 2 2 3
*For standard GE cables 704-659, -660, -661 and -662.