T1 PRI For PBX Telephony
A T1 PRI, also called an ISDN PRI, is a "Primary Rate Interface"
providing 23 individual digitized telephone lines plus data such
as Caller ID on a single digital telephone trunk line. A PRI line
is usually much less expensive than a dozen or more analog business
Advantage of Colocation Bandwidth
Colocation is locating your servers in a colocation facility,
also known as a carrier hotel. Advantages of this approach include
ready availability of low cost bandwidth including T1, DS3, Carrier
Ethernet and SONET Fiber Optic options. These data centers also
offer backup power, environmental control and high levels of security.
Channelized T1 vs ISDN PRI
T1 lines can support two protocols of switched circuit telephony.
Channelized T1 lines offer 24 phone lines using in-band signaling.
ISDN PRI, or Primary Rate Interface, offers 23 phone lines and
common channel signaling that can include data such as ANI Automatic
Number Identification or Caller ID.
T1 and T3 Lines for Wireless
A WISP or Wireless Internet Service Provider needs a way to connect
the Internet to the tower radios. T1 lines and bonded T1 lines
are widely used for this purpose, as well as cellular tower backhaul,
because of their almost universal availability. T3 lines offer
28x the bandwidth of T1 lines but are typically more available
in larger metropolitan areas.
T1 Line Bandwidth Explained
A T1 line is typically referred to as having a bandwidth of 1.5
Mbps. The precise line speed is 1.544 Mbps. However, the usable
bandwidth or payload is actually 1.536 Mbps. The difference is
8 Kbps which is used for line framing to keep the transmitting
and receiving ends of the circuit in synchronization.