Raytheon 2901 bit-slice processor family

Many second-source companies substituted their prefixes in part numbers with their own prefix, or used their own part numbers. Raytheon used AMD's part numbering convention for devices from 2901 family, which was uncommon for the time. To distinguish Raytheon 2900 parts from AMD parts look at the second (datecode) line of chip markings - the datecode line starts with "RAY" on Rayhteon chips.