Find the word definition

Wikipedia
SMODEM

Smodem refers to a bidirectional protocol for file transfer used between modems and the DOS program in which the protocol is implemented, both of which were developed by a Finnish company named Arisoft. It was mainly used in bulletin board systems because it could transfer files in both directions at the same time and allowed users to chat with each other with AriSoft's GroupChat software. Other popular bidirectional protocols such as BiModem, HS/Link and HydraCom also offered a chat option with the operator, but not with the system's other users.