Line Sense Reed Relay: Introducing the B1A-TEL, a tubular plastic case, dual coiled reed relay with a single reed switch inside it with the ability to be a small PWB mount loop current detector. The two coils can be bi-filar wound, or in the requirement of a higher voltage breakdown between the two coils, can be layer wound. Bi-filar winding means that the two coil wires are twisted together prior to winding the twisted pair on to the coil bobbin. Layer winding means that one coil is wound upon another with insulation existing between coils. Breakdown voltage of 500 volts and above can easily be expected.The actual coil resistance of the two wires used to make the coil must be accurately measured for end to end resistance for matching purposes. The reed switch magnetic sensitivity, what we call "ampere-turns" must be known exactly. A very narrow grouping of known reed switch sensitivities are selected for usage in the manufacturing of these unique reed relays.

These finished line sense reed relays meet all provisions of part 68 requirements for telephone applications to include voltage breakdown of each contact to the other contact and from contact to coil or coil to contact. The relays can be purchased with the leads formed to one inch centers and ends trimmed to extend 1/8 th of an inch beyond a thickness of a PCB. Other specifications are as per the drawing below.