Teledyne 9110E - Nitrogen Oxides Analyzer - Manual (Page 95)

Model 9110E Instruction Manual Operating Instructions
M9110E Rev B 81
Table 0-16: COM1 and COM2 DB-9 Pin Assignments
Pin # COM1 (RS-232) COM2 (RS-232) COM2 (RS-485)
1 Not used Not used Not used
2 TRANSMIT DATA* RECEIVE DATA DATA -
3 RECEIVE DATA* TRANSMIT DATA DATA +
4 Not used Not used Not used
5 Signal Ground Signal Ground Signal Ground
6 Not used Not used Not used
7 DATA SET READY* DATA SET READY Not used
8 REQUEST TO SEND*
(=DTE Ready) REQUEST TO SEND
Not used
9 Not used Not used Not used
* Configurable for COM1 at rear panel using the DTE-DCE switch
6.9.5. 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 (for COM1 only).
6.9.6. COM Port Communication Modes
Each of the analyzer’s serial ports can be configured to operate in a number of different
modes, which are listed in Table 0-17 and which can be combined by adding the Mode ID
numbers. For example, quiet mode, computer mode and internet-enabled mode would carry
a combined mode ID of 11, the standard configuration for Ethernet functionality on the
M9110E COM2 port. Note that each COM port needs to be configured independently.