The Unit Connectors AXIS 2120 User’s Manual

64

The Physical Connector

A single 9-pin D-sub connector provides the physical connection for the RS- 232 serial

interface of the AXIS 2120. This interface is for use with an external modem and is

suitable for speeds of up to 115kbps.

A diagram of the RS-232 connector complete with pinout information is shown below.

For pinout information concerning the AXIS 2191 Audio Module, see page 53.
The IO Connector

A 4-pole connector is provided for auxiliary IO connections to the AXIS 2120.

Physical Connector

The IO connector provides the interface to a single digital ou tput and a single digital input.

A diagram for the connector, complete with a pinout table, is provided below:

Pin Function
1CD (Carrier Detect) A view of the RS-232 connector as seen from
the rear of the AXIS 2120
2RXD (Receive Data)
3TXD (Transmit Data)
4DTR (Data Terminal Ready)
5GND (Ground)
6DSR (Data Signal Ready)
7RTS (Return To Send)
8CTS (Clear To Send)
9RI (Ring Indicator)
Pin Function
1Common Ground
2Positive Connection for DC Power Input or Output:
Electrically in parallel with the derived DC power for the unit, this pin may be used as a power
input or output. As a power input it can be used for remote applications to supply the AXIS
2120 via an external direct current source; for example, a 9-15V DC battery supply. Used as a
power output, it can drive the photo coupled input or other equipment; such as an infrared
sensor. The output voltage level is dependent upon the input voltage to the unit. A maximum
current of 50mA can be sourced from the DC output.
3Digital Input (photo-coupled anode):
Voltages 5-24V DC will activate the input. It is possible to use pin 2 to source the input.
4Digital Transistor Output:
With a maximum load of 100mA and maximum voltage of 24V DC, this output has an
open-collector NPN transistor with the emitter connected to pin 1. If it is to be used with an
external relay, a diode must be connected in parallel with the load for protection against any
voltage transients - as detailed in the Schematic Diagram, on page 66. Important!
Connecting AC to the transistor output will damage the unit.
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