Glossary
56K Voice Faxmodem Internal - User’s Guide 51
V.42
An ITU-T standard for modem communications that defines a two-stage
process of detection and negotiation for LAPM error control.
V.42 bis
An extension of ITU-T V.42 that defines a specific data compression
scheme for use during V.42 connections.
Xmodem
The first of a family of error control software protocols used to transfer
files between modems. These protocols are in the public domain and are
available from many bulletin board services.
XON/XOFF
Standard ASCII control characters used to tell an intelligent device to
stop/resume transmitting data.
Ymodem
An error-checking protocol that can send several files of data at a time in
1024-byte (1K) blocks. This protocol can use either checksums or CRC
for error checking.
Ymodem G
This is similar to Ymodem, except it relies on the modem for error
checking, which makes it faster.
Zmodem
This is similar to Xmodem and Ymodem, except it includes batch
transfer, the ability to recover from a partially complete transfer, an
autostart feature, and improved efficiency.