UUCP `e' Protocol
The `e' protocol is similar to the `t' protocol. It does no flow control or error checking and is intended for use over networks providing reliable end-to-end connections, such as TCP.
The `e' protocol originated in versions of HDB UUCP.
When a UUCP package transmits a command, it simply sends the command as an ASCII string terminated by a null byte.
When a UUCP package transmits a file, it sends the complete size of the file as an ASCII decimal number. The ASCII string is padded out to 20 bytes with null bytes (i.e. if the file is 1000 bytes long, it sends `1000\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0'). It then sends the entire file.