The Infra-Com mobile communications systems offer high quality voice communications where the area of reception is contained totally within a defined envelope. The true cellular approach of the Infra-Com digital mobile voice system allows exact areas to be covered, which can be increased or reduced at any time by adding or removing antennas.

The low powered infra-red does not penetrate walls and cannot be detected at any distance, making it ideal for confidential communications. In addition it is virtually impossible to jam and is not susceptible to radio, radar or electrical noise. Because of the absence of signal radiation in the radio bands both the fixed and mobile equipment will not cause any interference with other electronic equipment. Additional channels can be added up to the maximum of 8 in any one cell.

Each antenna has a controlled footprint of communication and many antenna can be simply inter-connected for a system of the desired size.

When used in a control centre up to 8 full duplex channels can be provided. Each of these channels allows full split headset operation where the operator can receive two independent signals at the same time. Alternatively, the system can be configured to provide a communications cell associated with only an individual desk or location.

The versatile lightweight headset mounted transceiver can be used with virtually any headset if the standard types are not acceptable. In a control centre or room environment the operator can receive telephone and radio calls simultaneously and can choose to which to reply, while maintaining complete freedom of movement.

There are no licence requirements.

In summary:
The low level infra-red digital encoding eliminates ocular hazards while providing exceptional coverage with multi-channel capability. The ability to employ virtually unlimited infra-red antennas, from one base station, ensures coverage over large areas. The use of encoding similar to CCITT G.711 guarantees outstanding quality of low noise voice communications which is full duplex on each channel. Side tone is generated in the base station giving complete confidence that communication is being achieved.

Mobile operators can communicate between each other or with external communication systems. The enhanced option allows for selective communications between a mobile user and either internal or external radio communications while receiving independent communications in each ear. This enhanced option also allows for broadcast communication to be received and local two way communications to be used independently, with the two communications channels in different ears.

Interference from electrical equipment is eliminated by the use of digitally encoded infra-red, allowing two way full duplex voice communications to continue in the most arduous electrical environments. Furthermore the use of low level infra-red ensures that sensitive electronic equipment is not effected by the use of the system even when in close proximity.

Small fixed infra-red antennas receive and transmit data between mobile users and the Base Station. These antennas are connected on simple "daisy chain" wiring throughout the area of coverage. This allows for a simple low cost installation which can be readily extended to cover additional areas as required, which can be undertaken by unskilled personnel. Using the maximum number of antennas areas up to 7500 square metres (75,000 square feet) can be covered by a single system.

A belt mounted battery pack carries the operator interface controls. These controls include the on/off switch, channel selection, volume control and press to talk button.

Although providing extensive life the battery pack can be rapidly removed and replaced with a recharged unit. A six channel conditioning battery charger is provided which can fully recharge a spent battery pack in under 2 hours. Alternatively a low cost simple battery charger is available which recharges a single battery pack.

The whole system has been designed for high reliability and availability with all MTBF calculated to the MIL-HDBK-217F.

The system has been designed to meet and has been extensively tested for both the lack of sensitivity to and the emission of electro-m agnetic radiation and is capable of withstanding severe energy pulses associated with radar and similar equipment. The equipment has been independently tested for environmental conditions, shock and vibration.