Knowledgebase Article
Knowledgebase > Network Access > Remote Access Server

What types of High Speed Facilities do the US use?
Article Id #: 273
 The US uses a T1 (message oriented or robbed bit) line. A message oriented line is a PRI (Primary RateInterface) ISDN line with 23B channels and 1 D channel. Instead of the phone company sending the ring voltage in-band with the data, the digital packet with the hook status is sent in its own channel (D channel) as an out-of-band signal (Common Channel Signaling). The gain from losing one channel (D channel which happens to be channel 24 on a T1) is that the 23 B channels are full 64K able DS0s and are not interrupted by calls coming in on the line. This is the line you want to use if you have users using a ISDN BRI (Basic Rate Interface) and a Terminal Adapter. This line also will tell you information like who is calling and what number was dialed. Robbed bit signaling is a type of in-band signaling (Channel Associated Signaling) used in T1 when the D channel is buried with the B channels, using the least-significant bits to indicate the hook condition. The least significant bits are "robbed" from each DS0 leaving a throughput of 56kb per second. Robbed bit signaling leaves you with 24 DS0s rather than 23 (remember you can only make ISDN BRI calls on a PRI that's the advantage, because the robbing of the bits only allows each DS0 56K and there is no digital channel to send digital packets on).
User Rating
This answer was helpful This answer was not helpful (8750 vote(s)) 
User Comments  Add a Comment )

Sales: / +1 301 975 1000
Support: / +1 301 975 1007
Join Our Email List
Have Us Contact You
Login Connect With Us
X Linkedin Facebook Youtube
     Patton LLC Copyright © 2022 All Rights Reserved.

|  Sitemap  |   Legal  |   Privacy Policy  |   Disclaimer  |    X  Facebook  YouTube  LinkedIn  RSS