As far as cryptography, the military AN-UGC/74 teleprinter worked with cryptographic equipment such as TSEC/KG-30, KG-84, KW-7, and KY-57 [1]. You'd send the data stream into the crypto equipment and then to the teleprinter. However, the modifications for the Space Shuttle would have prevented this. Specifically, the FSK demodulation boards for the Shuttle were wired directly to the communication UART board, so there was no place to plug in the crypto box.
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As far as cryptography, the military AN-UGC/74 teleprinter worked with cryptographic equipment such as TSEC/KG-30, KG-84, KW-7, and KY-57 [1]. You'd send the data stream into the crypto equipment and then to the teleprinter. However, the modifications for the Space Shuttle would have prevented this. Specifically, the FSK demodulation boards for the Shuttle were wired directly to the communication UART board, so there was no place to plug in the crypto box.
[1] https://radionerds.com/images/e/e0/TM_11-5815-602-24.pdf#pag...