The Krone 237A modules and wiring modules is a reliable and cost effective technique for installation of communications, broadcast and data wiring and has several advantages over solder tag methods, including significant time and maintenance benefits.
Krone offers a comprehensive range of connections and wiring system, based on a standard 10 pair (unscreened) termination module and a size compatible 6 pair + screen module. There is a complementary range of accessories for testing, alternative equipment termination, cable distribution and jumpering.
All items necessary for a Krone installation are featured in the Canford catalogue together with specially developed cable and accessories for the professional audio, data and broadcast industry.
Krone uses an insulation displacement connection which totally eliminates the need to strip, solder or screw connect wires. Connections are made using the Krone inserter tool on a slot in the module. The slot contains wire clamping ribs and two flexible metal contact arms at 45 degrees. These cut the wire insulation and into the conductor, maintaining contact with a spring force. A gas-tight seal is formed between the conductor and the contact. The inserter tool performs the process with the correct force and also cuts the excess wire off after termination with the same action. Krone connections conform to all the standards for contact resistance, ageing, and durability including British Telecom’s D2920 specification. The Krone technique can be learned in minutes by anyone, engineer or otherwise, and can cut installation time by up to 90%. Changes in wiring can be accommodated easily and re-termination is quick and neat.
A Krone module consists of two rows of contacts, the upper row for permanent connection, the lower row for jumper wires. Several types of module are available in two basic forms - connection and disconnection. Connection modules have a permanent link between the equipment and jumper sides, allowing 'listen' access for test probes and other accessories. The disconnection module has a spring contact connection between equipment and jumper sides, allowing 'listen' and 'break' access to circuits with appropriate test accessories. The disconnection modules have become universal in communications installations although some broadcasters prefer the connection type for premier grade circuits at the expense of some flexibility.
Each Krone connection slot will accept up to two wires of equal diameter. Ideally the conductor size will be 0.44mm to 0.65mm (26-22 AWG) and insulation 0.7mm to 1.4mm. The recommended wire is single strand 0.5mm conductor (standard telephone cable size per CW1308 spec). Stranded wire can also be used, 7/0.15 or 7/0.2 being preferred. The insertion of stranded wire may cut some strands, especially if smaller diameter conductors are used. Stranded and single core wire should not be mixed on a single contact slot.