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.htm (128 of 133) [11/28/2000 5:58:50 AM] Hacker's Handbook27B 1200 full duplex, sync or async (UK made)You should note that some commercial 1200/1200 full duplex modemsalso contain firmware providing ARQ error correction protocols;modems on both ends of the line must have the facilities, of course.** Page 142BT Line ConnectorsModems can be connected directly to the BT network ('hard- wired')simply by identifying the pair that comes into the building.Normallythe pair you want are the two outer wires in a standard 4 x 2 BTjunction box.(The other wires are the 'return' or to support a'ringing' circuit.)A variety of plugs and sockets have been used by BT.Untilrecently, the standard connector for a modem was a 4-ring jack, type505, to go into a socket 95A.Prestel equipment was terminated into asimilar jack, this time with 5 rings, which went into a socket type96A.However, now all phones, modems, viewdata sets etc, areterminated in the identical modular jack, type 600.The correspondingsockets need special tools to insert the line cable into theappropriate receptacles.Whatever other inter-connections you see behind a socket, the twowires of the twisted pair are the ones found in the centres of thetwo banks of receptacles.North America also now uses a modular jackand socket system, but not one which is physically compatible with UKdesigns.did you expect otherwise?** Page 143APPENDIX VIThe Radio SpectrumThe table gives the allocation of the radio frequency spectrum up30 MHz.The bands in which radio-teletype and radio-data traffic aremost common are those allocated to 'fixed' services, but data trafficis also found in the amateur and maritime bands.LF,MF,HF, RADIO FREQUENCY SPECTRUM TABLE9 -- 14 Radionavigation14 -- 19.95 Fixed/Maritime mobile20 Standard Frequency & Time20.05 -- 70 Fixed & Maritime mobile70 -- 90 Fixed/Maritime mobile/Radionavigation90 -- 110 Radionavigationfile:///E|/Books/Hackers Handbook.htm (129 of 133) [11/28/2000 5:58:50 AM] Hacker's Handbook110 -- 130 Fixed/Maritime mobile/Radionavigation130 -- 148.5 Maritime mobile/Fixed148.5 -- 255 Broadcasting255 -- 283.5 Broadcasting/Radionavigation(aero)283.5 -- 315 Maritime/Aeronautical navigation315 -- 325 Aeronautical radionavigation/Maritimeradiobeacons325 -- 405 Aeronautical radionavigation405 -- 415 Radionavigation (410 = DF)415 -- 495 Aeronautical radionavigation/Maritime mobile495 -- 505 Mobile (distress & calling) > 500:cw&rtty505 -- 526.5 Maritime mobile/Aeronautical navigation526.5 -- 1606.5 Broadcasting1606.5 -- 1625 Maritime mobile/Fixed/Land mobile1625 -- 1635 Radiolocation1635 -- 1800 Maritime mobile/Fixed/Land mobile1800 -- 1810 Radiolocation1810 -- 1850 Amateur1850 -- 2000 Fixed/Mobile** Page 1442000 -- 2045 Fixed/Mobile2045 -- 2160 Maritime mobile/Fixed/Land mobile2160 -- 2170 Radiolocation2170 -- 2173.5 Maritime mobile2173.5 -- 2190.5 Mobile (distress & calling) >2182--voice2190.5 -- 2194 Maritime & Mobile2194 -- 2300 Fixed & Mobile2300 -- 2498 Fixed/Mobile/Broadcasting2498 -- 2502 Standard Frequency & Time2502 -- 2650 Maritime mobile/Maritime radionavigation2650 -- 2850 Fixed/Mobile2850 -- 3025 Aeronautical mobile (R)3025 -- 3155 Aeronautical mobile (OR)3155 -- 3200 Fixed/Mobile/Low power hearing aids3200 -- 3230 Fixed/Mobile/Broadcasting3230 -- 3400 Fixed/Mobile/Broadcasting3400 -- 3500 Aeronautical mobile (R)3500 -- 3800 Amateur/Fixed/Mobile3800 -- 3900 Fixed/Aeronautical mobile (OR)3900 -- 3930 Aeronautical mobile (OR)3930 -- 4000 Fixed/Broadcasting4000 -- 4063 Fixed/Maritime mobile4063 -- 4438 Maritime mobile4438 -- 4650 Fixed/Mobile4650 -- 4700 Aeronautical mobile (R)4700 -- 4750 Aeronautical mobile (OR)4750 -- 4850 Fixed/Aeronautical mobile (OR)/Land mobile/Broadcasting4850 -- 4995 Fixed/Land mobile/Broadcastingfile:///E|/Books/Hackers Handbook [ Pobierz całość w formacie PDF ]