This disclosure relates to the transmission of binary data over a network between a transmission host and a receiving host. The transmission host receives packets of data including data in a first format which may be ASCII formatted and contain 6 bits-per-byte words, and including data which had an original binary format containing greater than 6 bits-per-byte words (such as 8 bits-per-byte) and which has been encoded (such as Uuencoded) to 6 bits-per-byte words. The transmission host searches the packets and identifies the encoded data and reverse codes the encoded data to its original binary format, before transmitting the data on a suitable network transmission media that can transmit both ASCII formatted data and data having greater than 6 bit-per-byte formats. The transmission host also includes an application packet demultiplexer for separating the incoming data according its application such as HTTP, NNTP, FTP, etc. The transmitting host includes an identifier in the packets for identifying the reverse coded data. The receiving host responds to the identifier and may encode the previously reverse coded data.