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 Lines are Full Duplex
T1 lines are bidirectional or full duplex. That means that you
can independently upload and download data at up to the full line
rate of 1.5 Mbps simultaneously. LANs that use switched Ethernet
are also full duplex, but LANs that use hubs operate at half-duplex.
A half-duplex network cannot transmit and receive at the same
time, cutting effective bandwidth by up to half.
How do T1 and DS1 differ?
In general conversation, T1 and DS1 refer to the same thing. But
strictly speaking, T1 refers to a physical line circuit consisting
of 2 pair of copper wires with strict line signal specifications.
DS1 stands for Digital Signal level 1. DS1 is the service level
you get on a T1 line. However, DS1 also is part of the digital
signal hierarchy used in T3 lines and SONET fiber optic carriers.