Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 123)

Operating Instructions Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 105
6.11.3. RS-485 Configuration of COM2
As delivered from the factory, COM2 is configured for RS-232 communications. To configure this port for
RS-485 communication, please contact the factory. If COM2 is configured for RS-485, the USB com port
is no longer enabled.
6.11.4. DTE and DCE Communication
RS-232 was developed for allowing communications between data terminal equipment (DTE) and data
communication equipment (DCE). Basic terminals always fall into the DTE category whereas modems
are always considered DCE devices. The difference between the two is the pin assignment of the Data
Receive and Data Transmit functions. DTE devices receive data on pin 2 and transmit data on pin 3;
DCE devices receive data on pin 3 and transmit data on pin 2.
To allow the analyzer to be used with terminals (DTE), modems (DCE) and computers (which can be
either), a switch mounted below the serial ports on the rear panel allows the user to switch between the
two functions.