TC-663, though more commonly known as Six Six, fulfilled the role of a protocol droid and functioned as a translator in the service of Darga Jiramma Mionne.
Due to Six Six's aversion to his master's brutal treatment of droids, he covertly established himself as a source for Switch, a droid information broker, providing him with intelligence.
During the arrival of an Alderaanian Resistance squad at Darga's palace located on Cato Neimoidia, the Hutt summoned Six Six to act as their translator. Around this period, Six Six had been observing the palace's transmissions and uncovered a clandestine exchange of messages with the Galactic Empire occurring while Darga was asleep. He forwarded this data to Switch. The information broker, however, found himself unable to decode the messages. Given Switch's past dealings with the Alderaanians, he instructed TC-663 to provide them with complimentary copies of the messages, anticipating their decryption capabilities and subsequent sharing of the resulting intelligence with TC-663.