Long frame jacks are designed especially for high quality communication equipment, and to meet exacting MIL specifications, as well as telephone and communication systems. Rugged steel frames are produced in specially designed dies, press welded to provide rigidity and dimensional stability required by telephone and communication jack panels - and to meet MIL frame strength tests. A and C frame styles are available. MT-Jax have solder lug terminals.
A single row of jacks can be installed with a single buss wire connected to all ground lugs in a row, or when double rows are mounted on .625" vertical centers with lugs oriented between rows, holes in ground lugs line up so a single buss wire provides connections for both rows.
MT-Jax jacks Numbers MT-342B and MT-344B have shorter bushings, 0.5" long with a hold inside diameter of .21". They will mate with MIL plug M642/5-1 or M642/8-1. M642/5-1 plug (Switchcraft 480) cannot be used with MT-342B or MT-344B if these jacks are mounted on standard .625" thick panels. The short jack bushings are recessed .125", and the M642/5-1 is too wide to fit in the panel recess. Use plug M642/8-1 (Switchcraft 484) with a narrower diameter to fit in the recess and mate properly.
Contacts on shunts and isolated switching circuits are welded crossbar palladium. Welded crossbar gold alloy contacts (WEco #1) are available on special order for dry circuit applications