Useful data (payload) may be encoded, packeted and exchanged through a protocol, and this may be what is called outgoing/incoming
So the protocol takes care of splitting data in packets, ordering and numbering them, resending if needed; the packets may contain header information, possibly trailer, control information (checksum etc), and the data may be endoed inside the packet
So transmitted data are packets sent at least once (may be repeated in case of errors) and received data are packets received in at least in one occurrence and in any order (ther protocol will sort this out)
But outgoing data are the useful payload of the packets, encoded before transmission and decoded at reception, and incoming data are the checked and decoded ccontent of received data, re-ordered if needed
http://www.makelinux.net/ldd3/chp-17-sect-5outgoing/incoming" may also be considered on a higher ISO model layer (application) than "transmitted/received" data
https://en.wikipedia.org/wiki/OSI_modelyour source context makes for sure two differences:
1) encryption
2) addition of a header
so you will for sure need different terms