S.T.C. Type 7030
| ||||||||
|
Used by other telephone administrations S.T. & C. 7030 type of P.A.B.X. This equipment provides most of the facilities set out in this paper and employs S.T. & C. uniselectors with 25 or 50 point banks, an 11 point "marker" switch and the S.T. & C. "flat" type of relay. An outstanding feature of thissystem is the unit formation adopted in which the inter-unit cabling is reduced to a minimum. All the units are of similar size, thereby making it an easy matter to compute the space required for a P.A.B.X. installation, before its erection on site.The line unit comprises one or two mounting plates, each containing 25 line and cut-off relays and their common equipment which are mounted one on each side of the rack.The connecting circuit unit comprises two connecting circuits, the relays being mounted on a plate on one side of the rack and the switches on a frame on the opposite side.The exchange line unit. Two complete junction equipments, of which one only need be equipped, are mounted in one unit.The power unit comprises the ringing and tone unit on one side together with the fuse alarm and junction starting relays. A rectifier, mains transformer, voltmeter and key panel are equipped on the other side.The battery of 24v is charged and discharged on the "floating" principle. The power equipment can be suitably modified to meet various types of main supply.Capacity of P.A.B.X. Extensions are numbered 25-99. Connecting circuits may be added as required. Exchange line circuits may be added as required. Group hunting may be employed over certain extension lines. Taken from a paper by the IPOEE dated 1932 (No. 142)
|
||||||||
Last revised: July 20, 2025FM | ||||||||
