Disclaimer I have never worked with crypto machines and do not have access to any classified information. Crypto 138 classified information appears on this or any of my other web pages. All the information is from open sources such as the internet and non classified manuals.
Army nomenclature, CSP-488 is the Navy name. The M-138-A is a strip cipher version. Used through the end of W. Used with a large number of radios for both voice, fax and data. Used with PRC-104 and other H.
What encryption system, what will it interoperate with? Replaces the KY-57 and other equipment. Uses a 40 character key based on 5-level paper tape. Originally designed to work with the PRC-77. Uses thumb-wheel switches to set key. There may be a shut down function that works by unit serial number.
PSN-11 GPS Receiver Can use a crypto key for reception of the GPS L2 frequency. Quantic Q5200 GPS Time Receiver Can use a crypto key for reception of the GPS L2 frequency. ASN-169 Version of the Trimpack that decodes encrypted L1 to avoid problems when SA was turned on. Requires key load for encrypted signals but works as civilian receiver without keys. This is the most common digital data application. Q modulation for Tx and Rx.