Installation Manual

AIS Installation Manual Issue 1 19

6 Electrical connections

This installation guide takes into account the IMO “Guidelines for installation of Shipborne

Automatic Identification System”. However both the IMO publication and these instructions must

be taken as guidance only; individual circumstances must take precedence.

This guide is concerned only with the installation of the AIS transponder unit and does not cover

the installation of any peripheral equipment connected to the transponder. For proper

installation and connection of peripheral equipment to the transponder refer to the installation

manuals for these products.

Connection Must connect Optional

24.0 VDC power supply* Yes

GNSS antenna Yes

VHF antenna Yes

Display system Yes

Position (external GNSS) Yes

Heading (vessel gyro) Yes

Pilot plug See Note 1 See Note 1

Alarm Relay Yes

ECDIS (Main port) Yes

ARPA (Main port) Yes

Long range function Yes

RTCM, differential GNSS info. Yes

Rate of turn Yes

Speed and Course Yes

*WARNING: Ensure supply is compatible with voltage and current requirements.

Note 1: depends on IMO recommendations and local legislation.

6.1 Ground Connection

The earth stud on the transponder backplate must be connected to ship’s ground. The

recommended connector wire is 4 mm

, green/yellow colour.

6.2 Signal cable connections for AIS Transponder

As shown in the table above, the AIS Transponder must be or may be connected to different

types of peripheral units; these can be divided in three groups:

• Coax connection to the antennas

• signal cable connection to the sensors (GNSS, Gyro, Log)

• signal cable connections to the five-input/output ports (Main, AUX/Pilot, long-range,

RTCM, Display)

Connecting the three types of interfaces is described in detail in the following sections.

The signal connections are all connected via a serial RS422 type interface; data rates are

normally 4800 or 38400 baud.

In some cases, particularly in retrofit installations, it may not be possible to connect the AIS

directly to the required sensor, because some sensors do not provide the IEC 61162-2 (NMEA)

sentences required by the AIS unit. In such cases a protocol converter is required between the

sensor and the AIS unit. Converters are available from different manufacturers, either as direct

protocol converters or frequently as repeater instruments for the sensor. A Gyro Interface Unit,

P/N 89-028, is available from McMurdo as an optional extra.