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
Channelized and Unchannelized
A T1 line may be configured as a single large pipe offering 1.5
Mbps data transport or as 24 individual channels of 64 Kbps each,
ideal for use as individual outside telephone lines to support
Key or PBX business telephone systems.
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.
Bandwidth to Support Convergence
Convergence means combining or converging voice, data and video
onto a single network. Enterprises usually need to expand their
LAN bandwidth and set up a QoS or Quality of Service priority
system to give priority to real-time streams such as telephone
calls or video conference feeds, which are more sensitive to network
delays than data transfers. Most often, the common protocol for
convergence is IP.