User's Manual

SEL-3021 Transceiver Instruction Manual Date Code 20041005
Introduction & Specifications
Connections, Reset Button, and LED Indications
1.6
Figure 1.4 Typical Alarm Output Installation
Serial Port Pin-Out Connection
The SEL-3021 has a fully compliant DTE and DCE serial port. SEL offers many cable
configurations for use between the SEL-3021 and other devices.
The serial port pin-out descriptions for the DTE and DCE ports are as follows.
Ta b le 1 .1 DT E ( M ale DB 9 )
Pin Description
1 Data Carrier Detect (Input)
2 Received Data (Input)
3 Transmitted Data (Output)
4 Data Terminal Ready (Output)
5Ground
6 Data Set Ready (Input)
7 Request to Send (Output)
8 Clear to Send (Input)
9 Ring Indicator (Input)
SEL-3021
Alarm Output Contact
Do not apply 125 Vdc
directly to the SEL-3021
power supply connections
Typical SEL contact
inputs draw 4 mA of
nominal wetting source voltage
SEL-2030
Contact Input
Wetting Voltage
125 Vdc
0.5 A, 250 V
Fast Blow Fuse
Optional Load
Resistor
+
—
Preliminary Copy