ZMODEM

A public domain file transfer protocol used in asynchronous data communications. ZMO-

DEM offers a number of improvements to the earlier XMODEM protocol, including an expanded 32-bit cyclic redundancy check (CRC) for purposes of improved error control. ZMODEM also supports larger block sizes (512 bytes), allows a transmission to resume where it left off in the event of a communications failure, and reduces latency through a sliding window protocol that allows a modem to transfer a series of blocks without waiting for individual acknowledgements from the receiving modem. ZMODEM was

developed by Chuck Forsberg in 1986 for use in the Telenet X.25 network, and quickly became popular in the bulletin board system (BBS) community for file downloads. See also asynchronous, BBS, block, CRC, error control, Kermit, modem, X.25, XMODEM, and YMODEM.

• North American Numbering Plan (NANP)
• North American Time Division Multiple Access (NA-TDMA)
• NOS (Network Operating System)
• notation
• Not To Act Like It)
• Novel Services)
• NPAC (Number Portability Administration Center)
• NPA (Numbering Plan Administration)
• N-PCS (Narrowband Personal Communications Services)
• NREN (National Research and Education Network)
• nrt
• nrt-VBR (non real-time Variable Bit Rate)
• NRZ (Non-Return-to-Zero)
• NSF (National Science Foundation)
• NT1 (Network Termination 1)
• NT1 (Network Termination 1)
• NT2 (Network Termination 2)
• NT2 (Network Termination 2)
• NTACS (Narrowband Total Access Communications System)
• NTIA
• NT (Network Termination)
• NTSC (National Television Standards Committee)
• null
• null modem
• numbering plan administration (NPA)