electronic mail standard identification (EMSI)

The Electronic MailStandardIdentification (EMSI) is a frequently used connection protocol in FidoNet. The EMSI protocol is used to exchange user IDs, passwords and to authenticate and identify the communication partners. After the exchange of the connection data and the start of the mail transmission, the user data is transmitted in a protocol that is similar to Z- Modem and has a block size of 8 KB for the user data.