A better balun

One of the problems faced by telecomms OEMs is the need to meet varying interconnection standards with their equipment. In some countries, 2Mbit/sec signals are carried over 75Ohm coax while others use 120Ohm twisted pair.

To date, the equipment manufacturer has had only two choice: either he could produce two different types of equipment for the two standards, or he could produce equipment to meet one standard and some form of add-on to adapt to the other.

Now, there’s a better solution, thanks to the designers at Basingstoke-based ITT Canon. Their new balun can provide the change from 75Ohms to 120Ohms within the connector on one end of the interconnecting cable. The small size means that this can be fitted into all standard mounting arrangements, without having to provide special or non-standard panels. What’s more, because designers now only need to design one type of equipment, they can pick up economies of scale and reduce inventory.

The device itself can be fitted to a screened or unscreened twisted pair through IDC contacts, making the termination quick and simple. The balun itself is supplied as a pre-assembled connector together with two plastic mouldings that provide cable support and alignment of the wires in the cable. The balun can be terminated to the appropriate twisted pair cable, using a specially designed termination tool in three simple stages. First, the plastic housing and piece block are threaded onto the stripped cable. Then, the insulated wires and drain wire are laid in the appropriate slots in the pierce block and excess wire is trimmed flush with the underside of the flange. Finally, the connector body is aligned with the plastic parts, placed in a termination tool, which completes the assembly.

The whole device measures 10 by 10mm.

ITT Canon. Tel: 01256 311200.