T1 / T3 Services (1)
The highest frequency transmitted for voice communication is 4 kHz. In order to recreate the analog wave from digital stream of data, we need to sample the analog wave at twice the rate of the highest frequency, it means 8 KHz = 8000 times per second. To represent 4KHz in digital, we generate 8-bit samples 8000 times per second. (Voice channel = 64,000 bps)
Service Class:
- DS0 the basic 64 Kbps channel in digital voice networking
- DS1 collection of 24 DS0 = 1.544 Mbps
- DS2 28 DS1 channels (this service is not commonly available)
- DS3 7 DS2 channels or 672 DS0 channels = 44.736 Mbps
T-carrier services are traditionally dedicated, but switched services are also available. T-carrier services are typically leased on a month-to-month basis and include initial setup charge.