Dte Versus Dce Communication; Table 6-14: Com-A And Com-B Default Pin Assignments - Teledyne 300E Instruction Manual

Model 300E Carbon Monoxide Analyzer
Instruction Manual
Table 6–14: COM-A and COM-B Default Pin Assignments
PIN #
1
2
3
4
5
6
7
8
9
1
* Switchable for COM-A at Rear
Panel using the DTE-DCE switch

6.8.4. DTE versus DCE Communication

RS-232 was developed for allowing communications between Data Terminal
Equipment (DTE) and Data Communication Equipment (DCE). Dumb Terminals
always fall into the DTE category while modems are always considered DCE's. The
difference between the two is which pin is assigned the Data Receive function that
is assigned the Data Transmit function. DTE's receive data on pin 2 and transmit
data on pin 3. DCE's receive data on pin 3 and transmit data on pin 2.
To allow the analyzer to be used as either a DTE or DCE without the need for a
special adapter, there is a switch located just below the connector for COM-A that
switches COM-A between DTE and DCE.
P/N 04288 REV: A
COM-A (RS-232)
Not Used
TRANSMIT DATA*
RECEIVE DATA*
Not Used
SIGNAL GROUND
Not Used
DATA SET READY*
REQUEST TO SEND*
(=DTE Ready)
Not Used
2 3 5
* *
4
7 8
6 9
COM-B (RS-485)
Not Used
DATA+
DATA-
Not Used
SIGNAL GROUND
Not Used
Not Used
Not Used
Not Used
5 4
8
9
Operating Instructions
COM-B (RS-232)
Not Used
TRANSMIT DATA
RECEIVE DATA
Not Used
SIGNAL GROUND
Not Used
DATA SET READY
REQUEST TO SEND
Not Used
2 1
3
7 6
91