Remote Operation; Rs-232 Serial - API 8512 Series Operation & Installation Manual

4. Remote Operation

4.1. RS-232 Serial

The RS232 port is available on a DE9M connector and utilizes three signals: TXD, RXD and GND along with the
optional RTS and CTS handshaking signals. The connector pinout is configured as a DTE device, so connections
to an external DTE device (such as a PC) would require the use of a null-modem cable. The format is fixed at N81
(no parity, 8 data bits, 1 stop bit), and the baud rate is selectable via software command at rates of from 9600 to
230400. By default, the unit is shipped to operate at 115200 baud, with the Console mode non-volatile memory
(NVM) setting enabled (see below).
The serial port has two modes of operation: console and raw mode. Console mode provides a command-line
interface (CLI) and is useful for interactive control via a terminal emulator. The Console mode sends command
prompts ('>'), echoes received characters, supports the backspace key for simple editing, provides command line
recall (CTRL-R), and issues error messages, while raw mode is a basic serial interface with none of these features
and is typically more suitable for programming. The selection of raw versus console mode is done via the
CONSOLE command, which can be used to enable/disable the console feature and optionally save the desired
setting in non-volatile memory (see the CONSOLE command in the command reference for additional options).
A Null Modem cable for DTE to DTE communication requires the TX/RX and CTS/RTS pins to be swapped at one
of the connections. A wiring example is show below.
Remote Operation
Figure 1: RS-232 DE9M (DTE Pinout)
Pin Signal
1
2 RXD
3 TXD
4
5 GND
6
7 RTS
8 CTS
9
RS-232 Null-Modem Cable (DTE to DTE)
DE9F
1
RXD 2
TXD 3
4
GND 5
6
RTS 7
CTS 8
9
Name Direction
Receive Data In
Transmit Data Out
Signal Ground
Request To Send Out
Clear To Send In
DE9F
1
2
3
4
5
6
7
8
9
MANUAL IM635
Signal
RXD
TXD
GND
RTS
CTS
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