V. Upper case V, {ASCII} character 86, known in {INTERCAL} as book. 1. A testbed for distributed system research. 2. Wide-spectrum language used in the knowledge-based environment {CHI}. "Research on Knowledge-Based Software Environments at Kestrel Inst", D.R. Smith et al, IEEE Trans Soft Eng SE-11(11):1278-1295 (1985). V.10. An {ITU-T} recommendation on electrical characteristics for {unbalanced} {double-current interchange circuits} operating at {data signalling rates} nominally up to 100 kbps. This recommendation is also included but not published in {ITU-T} X series under alias number X.26. The circuit defined in this standard is used in other {serial line} standards such as {EIA-232} and {EIA-423}, that implement {single ended} communication. (2002-10-05) V.11. An {ITU-T} recommendation on electrical characteristics for {balanced} {double-current} {interchange circuits} operating at {data signalling rates} up to 10 Mbps. V.11 is also included but not published in the as {ITU-T} X.27. V.11 is used in other {serial line} standards such as {EIA-422} and {EIA-485}, that implement {differential line} communication. (2003-04-06) V.17. An {ITU-T} {modem} {protocol} for 14400 {bps} {half duplex} communications with {fall back} to 12000 {bps}, 9600 {bps} and 7200 {bps}. (2004-07-26) V.21. 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. (1996-07-22) V.22. An {ITU-T} {modem} {protocol} which allowed data rates of 1200 {bps}. {V.22bis} doubled this. (2004-07-26) V.22bis.{V.22} twice. An {ITU-T} {modem} {protocol} which allowed a data rate of 2400 bits per second, twice that of {V.22}. V.23. An {ITU-T} {modem} {protocol} which allowed {half-duplex} (unidirectional) data transmission at 1200 bits per second with a 75 {bps} {back channel} and {fall back} to 600/75 bps. This was the main standard used for {British Telecom}'s {Prestel} service. (2004-07-26) V.24. The {ITU-T} {standard} defining interchange circuits between {DTE} and {DCE}. V.24 is the {ITU-T} equivalent of {EIA} standard {EIA-232C}, though V.24 only specifies the meaning of the signals, not the connector or the voltages used. V.24 recommends 12 {modem} {carrier} frequencies that will not interfere with {Dual Tone Multi-Frequency} or other telephone control tones. These are: GROUP A = 920 Hz, 1000 Hz, 1080 Hz, 1160 Hz GROUP B = 1320 Hz, 1400 Hz, 1480 Hz, 1560 Hz Group C = 1720 Hz, 1800 Hz, 1880 Hz, 1960 Hz (2004-08-02) V.25. A {standard} allowing an {auto-answer} {modem} to determine the correct {modulation} standard to use. (2001-04-06)
