4-letter words that end in 21
- v.21 — (protocol, standard) An ITU-T modem protocol for 300 bps two-wire full-duplex communications using Frequency Shift Keying modulation. All modern modems support both V.21 and the close variant, Bell 103.
- x.21 — (communications, standard) A digital signaling interface recommended by ITU-T that includes specifications for DTE/DCE physical interface elements, alignment of call control characters and error checking, elements of the call control phase for circuit switched services, data transfer at up to 2 Mbps, and test loops. 64 kbps is the most commonly used transfer rate.
On this page, we collect all 4-letter words ending in 21. It’s easy to find right word with a certain length. It is the easiest way to find 4-letter word that ends in 21 to use in Scrabble or Crossword puzzles.