Soviet Speed Dialer with Magnetic Core Rope Memory

Prior to the development of semiconductor read-only memory (ROM), core rope memory was one technology used to store constant binary data. The software for the Apollo Guidance Computer was stored in 36,864 16-bit words of hand-woven rope memory. Data are encoded by weaving a wire through magnetic cores, passing through the core denoting one binary value and around it the other.

Yes, the customer had to manually weave a wire for each of the 40 numbers it could dial through an array of 28 magnetic cores, representing a 7 digit telephone number as binary coded decimal digits.

2 Likes