[go: nahoru, domu]

Modem: Difference between revisions

Content deleted Content added
t5
Tag: Reverted
Line 443:
A "short haul modem" is a device that bridges the gap between leased-line and dial-up modems. Like a leased-line modem, they transmit over "bare" lines with no power or telco switching equipment, but are not intended for the same distances that leased lines can achieve. Ranges up to several miles are possible, but significantly, short-haul modems can be used for ''medium'' distances, greater than the maximum length of a basic serial cable but still relatively short, such as within a single building or campus. This allows a serial connection to be extended for perhaps only several hundred to several thousand feet, a case where obtaining an entire telephone or leased line would be overkill.
 
While some short-haul modems do in fact use modulation, low-end devices (for reasons of cost or power consumption) are simple "line drivers" that increase the level of the digital signal but do not modulate it. These are notnotp;0[0--[t44y56775y65y656y5h4y645y4t54qytqy6y6qay6y4Y4 technically modems, but the same terminology is used for them.<ref>{{Cite web|title=Modem|url=http://www.trine2.net.au/Modem-Tutorial(YES!)/modem.htm#Short_Haul|access-date=2020-08-13|website=www.trine2.net.au}}</ref>
 
==See also==