Apollo Command Module Block II Audio Center Equipment (ACE) measuring approximately 4.75 x 10.5 x 6, labeled “C28-1A111.” The unit has four connectors, “J1” through “J4” on the top, with the latter two bearing auxiliary cables, with one featuring part number: “ME414-0467-1004, 6607E-Deutsch PAT. 17292-37-7SY-1.” One end bears scratched off ID numbers, the opposite end stamped, “Serial No. 0006, Assy. 514-0040-010,” and two sides affixed with label: “Engineering Test Unit, Not For Flight, Parts/Assemblies Removed, Must Be Marked As Above.” In fine condition, with end of one auxiliary cable cracked. The ACE enabled communications among astronauts, between astronauts and launch personnel, and post-landing recovery frogmen; via the external communications links (Unified S-Band and VHF) to JSC Houston and the Lunar Module, as well as routing of audio to the Data Storage Equipment (DSE) for recording of audio signals.
Terms and abbreviations used in our descriptions.