Avaya Communication Manager Administrator's Manual page 1743

Type of trunk
ISDN
PCOL
SIP
Tie, Access
Transmission and supervisory signaling
A trunk is named for its transmission characteristics. For example, trunks are always classified by the
direction of the traffic they allow:
•
One-way incoming trunk
media server or switch.
•
One-way outgoing trunk
server or switch.
•
Two-way trunk
Another transmission characteristic is signaling, which is the transmission of supervision, address,
alerting, or other switching information. Supervisory signaling establishes or sets up the connection of
the local media server or switch to the distant server or switch. In general, supervisory signaling has 2
phases:
•
Seizure signal
•
Start-dial signal
originating office.
Seizure signals
Ear & Mouth (E&M) supervision
E&M supervision is a symmetric signaling scheme used on private network trunks. DC voltage levels are
sent over E&M leads, which are separate from the transmission path. E & M signals indicate on-hook and
off-hook states for each end of the connection path.
Administrator's Guide for Avaya Communication Manager
November 2003
Analog or
Direction Digital?
Incoming Digital
Outgoing
Two-way
Incoming Analog
only
Outgoing
Two-way
Incoming Digital
Outgoing
Two-way
Incoming Either
Outgoing
Two-way
—
A local trunk that can be selected (seized) by the far-end connected
—
A trunk that can be seized by the local switch to call the far-end
—
A trunk that can be seized by either of the connected servers/switches.
—
The originating office's signal for a request for service from the distant office.
—
The distant office's acknowledgment that it is ready to accept dialing from the
Trunks and trunk groups
Transmits
Traffic supported digits?
Any kind of voice or Yes
voice grade data.
Only voice and No
voice-grade data.
Voice only Yes
Any kind of voice or Yes
data traffic.
Feature Reference
1743