A plated wire read only memory module

An electrically alterable read only memory module using NDRO plated wire cables has been designed to store the fixed programs of electronic exchange systems. The capacity of the memory system is 1080 kbits (4 modules) and the read cycle time 1.44 μs. The magnetic film of plated wire consists of five layers (Permalloy and Ni-Co films) on 0.1-mm-diameter Be-Cu wire. The 72-pair plated wires 50 m long are laminated between polyester tapes and are formed as a plated wire cable. A pair wire forms a bit (2 cross point/bit). The memory module consists of 16 memory planes stacked and involves 8192 33-bit words (270 336 bits) in total. An address has 8 words and is selected through a diode matrix built in the module. The plated wire cables are folded with no interconnection like the twister module. The digit (Id) and word current (Iw) operating ranges in this module are 68 to 92 mA and 270 to 320 mA, respectively. 5 mV is specified as an allowable minimum output voltage. The ambient temperature range of this module is from 10 to 40°C. The temperature coefficient of the output voltage is approximately 0.0065/°C.