T1 / T3 Services (3)
Frame: a group of all 24 T1 sub-channels with 8 bits per channel and one framing bit. One frame equals 193 bits; 12 frames = D4; 24 frames = ESF
Channelized T1 - used to supply 24 individual channels to different locations
E1 - 32 DS0 channels = 2,048 Kbps (in Europe) AMI is not used; B8ZS is replaced by HDB3 encoding (High Density Bipolar)
Devices required:
- CSU / DSU = Channel Service Unit / Digital Service Unit
- V.35, EIA RS449 or RS 530 interface to DTE; RJ48C or RJ48X jack
LAN---bridge --(V.35)---CSU/DSU---(T1)---CSU/DSU--(V.35)---bridge--LAN
Bell Atlantic: installation $622; usage $642/month (in 1997)