cas-group

Syntax

cas-group {time-slots time-slots; signaling { fxo-loop-start;fxo-ground-start;fxs-loop-start;fxs-ground-start;em-wink-start;}}

Hierarchy Level

[edit services convergence-services trunk trunk-name trunk-type t1

Release Information

Statement introduced in Release 10.0 of Junos OS.

Description

Configure channel associated signaling (CAS) for T1 interfaces. CAS specifies a signaling method in which the signal is associated with the channel. Each of the time slots for the preconfigured T1 interface is associated with an individual channel. The 24 channels together form a frame. A T1 interface can carry up to 24 calls using two-wire pairs.

Specify the range of time slots or individual time slots dedicated to voice on the preconfigured interface. The system keeps track of which time slots are in use and sends a call out on the next available channel. For T1 interfaces, CAS uses a technique referred to as robbed bit signaling, in which an additional bit taken from the T1 frame is used for framing synchronization.

Options

time-slots: Range of time slots on the T1 interface to be use for voice. Specify the time slots to be used in the following format, for example 1-5, 9.

signaling:

fxo-loop-start or fxs-loop-start—Signaling for FXO interfaces or FXS interfaces. Loop start signaling is one of the simplest forms of CAS signaling. When the handset is picked up (the telephone goes off-hook), it closes the circuit that draws current from the telephone company (telco) and indicates a change in status, which signals the telco company to provide a dial tone. An incoming call is signaled from the telco to the handset by sending a signal in a standard on/off pattern, which causes the telephone to ring.
fxo-ground-start and fxs-ground-start—Signaling for FXO interfaces or FXS interfaces (fxo-ground-start or fxs-ground-start). Ground-start signaling is a technique in which a party gets a dial tone by momentarily grounding one side of a two-wire trunk.
em-wink-start—Ear-and-mouth-wink start is an in-band signaling method that defines a trunk-circuit side and a signaling unit side for each connection.

Usage Guidelines

For configuration instructions and examples, see the Junos OS Integrated Convergence Services Configuration and Administration Guide.

Required Privilege Level

services—To view this statement in the configuration.

services–control—To add this statement to the configuration.