0 a metal pin at the end of a long wire joined to a piece of electrical equipment and used to connect it to another piece of electrical equipment --
Most telephone exchanges then used human operators and cord boards to switch telephone calls by means of jack plugs.
A phone connector or jack plug in the rear of the unit permits a set of test leads to be plugged in effecting a quick conversion between the two applications.
It drives earphones with 3.5 stereo jack plug.
It said that the batteries were not secured and that the jack plug might be taped to the side.
It said that the radio would not work and could be armed by plugging in an antenna jack plug.
