efb@ames.arc.nasa.gov (Everett F. Batey II) (10/17/88)
Not long ago we had threats that would have ended UUCP and local host fast
dialins .. we were told. More recently ( first plans fell thru, usual bureau-
cracy ) we hear rumors that GTEL will be furnishing us an ALL DIGITAL phone
system.
Can anyone tell me what the likelihood is of fast UUCP ( 9600 - 19200 ) being
able to survive the didital dial lines or fast user host dial in out being
possible without buying separate analog lines. I understand analog / digital
lines is frequently used losely to describe COs as well as local equipment
and MUXing facilities. All I know is the above and I urgently need educating
as the Phone-Czars are playing national_secret. help .. thanks /Ev/
--
suned1!efb@elroy.JPL.Nasa.Gov sun!tsunami!suned1!efb efbatey@NSWSES.ARPA
Any statements / opinions made here are mine, alone, not those of the
United States, the DoD, the Navy, the Congress, the Judiciary, nor ...brian@umbc3.UMD.EDU (Brian Cuthie) (11/03/88)
In article <telecom-v08i0162m07@vector.UUCP> elroy!suned1!efb@ames.arc.nasa.gov (Everett F. Batey II) writes: >X-Administrivia-To: telecom-request@vector.uucp (USENET Telecom Moderator) >X-TELECOM-Digest: volume 8, issue 162, message 7 > >Not long ago we had threats that would have ended UUCP and local host fast >dialins .. we were told. More recently ( first plans fell thru, usual bureau- >cracy ) we hear rumors that GTEL will be furnishing us an ALL DIGITAL phone >system. > If you are describing a DIGITAL SWITCH then you will likely not see the difference. Although, some of the early DMS-100 installations had problems with bit slip because they were not synchronized correctly to a master clock. To my knowledge this has been fixed. If what you are describing is what is know as DIGITAL LOOP service then you may run into some difficult problems (although I don't know of any digital loop services actually in use other that PBXs). Many newer PBXs use digital loops. In a digital switch, incoming analog (read normal) phone lines are PCM encoded. Then, the data is switched onto PCM highways (really high speed buses). This is the wave of the future since switching is done in time domain rather than space domain. Some newer switches allow the PCM data to be extended all the way to the phone. The advantage is that the phone, it's nice display and buttons are all powered by the loop. Also, since the PCM CODEC is in the phone, high quality audio may be acheived by using decent microphones in the handset. The problem is that any equipment (read: modem) that expects a normal phone line WILL NOT WORK. If you plan to use a modem through such a switch it is necessary to either get an analog line or to use a modem pool. Many well equiped digital switches take advantage of the digital loop, which often has bandwidth in excess of 256Kbps, to pass user data as well as PCM voice and control. These systems usually allow a < $200 option to be added to the phone which presents a normal DCE connector. Modems are then "pooled" at some central location. Users needing to place outside data calls are routed to an available modem and the call is placed for them. -brian -- Brian D. Cuthie uunet!umbc3!cbw1!brian Columbia, MD brian@umbc3.umd.edu