RS232 SURGE SUPPRESSION

Realising the importance of avoiding downtime in mission critical or business critical environments, Uniterm have developed a cost-effective solution to lightning strikes in the form of the ZEUS surge suppression module.

Telecommunication equipment is frequently subject to damage caused by transients. These surge voltages may result from atmospheric fields and discharges (lightning), interference from power lines or switching effects within the system. The basic requirements of a shunt element protector is to be a voltage suppressor initially, followed by being a current divertor and it should not interfere with the normal operation of the equipment.

The Uniterm ZEUS is constructed to meet the most stringent requirements as regards overvoltage protection and complies with international CCITT standards.

The Zeus is available in single, four and up to eight module configurations. Each module comprises either three or four protection circuits (channels).

Each protection circuit constitutes five components. The Shunt element comprises Gas Discharge Tube, Metal Oxide Varistor and Silicon Transient Suppressor. These three active components are linked indirectly parallel by reactive Chokes to provide maximum protection against line transients.

CONNECTIVITY AND INSTALLATION

The ZEUS modules can be terminated with a male or female gender DB-25 connectors and with three or four protection channels per module. Protection channels are terminated on pins 2,3,(4) and 7 of the DB-25 connector.

It has already been mentioned that a shunt protector should be a voltage suppressor followed by a current divertor, however, the performance of both these features can be seriously affected by improper connections due to poor grounding practice.

 

For the ZEUS installation to be successful the Host machine and Multi I/O module(s) must share a common ground with the ZEUS module(s) and data terminals. This common ground should be strapped to an Earth bus with a low resistivity to natural ground.

The shield/screen wire of the RS232 transmission cable should be terminated at pin1 of the ZEUS module DB-25 connector. The ZEUS is supplied with an earth strapping cable which should be connected between the chassis of the ZEUS and a good earth point.

Uniterm Design & Manufacture