Specifications

Appendix C. Serial Port Pin Outs
C-2
C.2 RS-232 Communications Port
Pin configuration for the CR1000 RS-232 9-pin port is listed in TABLE C-2.
Information for using a null modem with the RS-232 9-pin port is given in
TABLE C-3.
The Datalogger RS-232 port can function as either a DCE (Data
Communication Equipment) or DTE (Data Terminal Equipment) device. For
the Datalogger RS-232 port to function as a DTE device, a null modem cable is
required. The most common use of the Datalogger's RS-232 port is a
connection to a computer DTE device. A standard DB9-to-DB9 cable can
connect the computer DTE device to the Datalogger DCE device. The
following table describes the Datalogger's RS-232 pin function with standard
DCE naming notation. Note that pins 1, 4, 6 and 9 function differently than a
standard DCE device, this is to accommodate a connection to a modem or other
DCE device via a null modem.
TABLE C-2. Datalogger RS-232 Pin-Out
PIN = Pin number
O = Signal Out of the CR1000 to a RS-232 device
I = Signal Into the CR1000 from a RS-232 device
X = Signal has no connection (floating)
PIN
DCE
Function
Logger
Function I/O Description
1 DCD
DTR (tied to pin
6)
O* Data Terminal Ready
2 TXD TXD O
Asynchronous data
Transmit
3 RXD RXD I
Asynchronous data
Receive
4 DTR N/A X* Not Connected
5 GND GND GND Ground
6 DSR DTR O* Data Terminal Ready
7 CTS CTS I Clear to send
8 RTS RTS O Request to send
9 RI RI I* Ring
* Different pin function compared to a standard DCE device. These pins will
accommodate a connection to modem or other DCE devices via a null modem
cable.