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
phone lines.
Bonding T1 Lines for Higher
Bandwidth
While a standard T1 line provides 1.5 Mbps upload and download
bandwidth, lines can be bonded to create total bandwidths of 3
Mbps, 4.5 Mbps, 6 Mbps, 7.5 Mbps, 9 Mbps, 10.5 Mbps and 12 Mbps.
An advantage T1 lines have over fiber optic connections is that
they are available nearly everywhere without special construction.
What Are Pseudowires?
A pseudowire is a virtual "circuit" that emulates a
traditional digital telecom service but on a packet switched network.
MPLS networks are especially suitable for pseudowires. By using
a pseudowire circuit, you can get the point to point connectivity
you desire without having to re-engineer your facilities to accommodate
a different protocol network.
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.
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.