In message <Pine.SUN.3.91.970628111459.3115L-100000(a)crl4.crl.com> classiccmp(a)u.washington.edu writes: I think this is what it says it is - a data encyption/decryption system. I have a thing called a 'modem maximiser' (a serial port data buffer box with a real time clock, parallel printer port, etc) that has an optional encryption unit. It too was a potted module. As I had a few spare modules I cut one apart and found it contained an 8032 (I think) microcontroller, RAM, a ROM (I must desolder that and examine it) and a TTL latch. Pretty much what you'd expect - a little microcontroller that reads in data, encrypts it, and sends it out again. -tony