Specifications

Product Overvie

0003097 Revision A

• The peripheral switch controller sends a message to main control when the destination

set answers the call.

• The main control establishes a circuit switch voice path by connecting the source to the

destination.

• The system’s tone generator supplies all audible tones (such as dial tone, busy tone, and

ringback tone) to the circuit switch for distribution to callers as required.

• At the Peripheral Interface card, voice signals from each telephone are converted into

digital form (pulse code modulation) and routed through the system on the established

circuit; signals leaving the switch are decoded back into analog form by the Peripheral

Interface card.

Lines and Trunks

Lines

The system supports the following types of internal voice lines:

• Digital Network Interface (DNI) Lines provide an interface for Mitel digital telephones,

consoles, and datasets. The maximum loop resistance on a DNI line must be 280 ohms

or less, and the loop length must be 3300 ft. (1000 m) or less on 26-gauge wire.

These lines are supported by the Digital Network Interface line card.

• On-Premises (ONS) Lines (24 V per port) are for industry-standard rotary dial and DTMF

telephones. The external loop resistance on an ONS line must be 600 ohms or less, and

the loop length must be 5000 ft. (1500 m) or less on 26-gauge wire.

These lines are supported by the ONS line card and the ONS CLASS/CLIP line card.

• Off-Premises (OPS) Lines (48 V per port) are for industry-standard telephones where

the external loop resistance exceeds 600 ohms or where lightning surge protection is

required. The maximum loop resistance on an OPS line must be 1800 ohms or less, and

the loop length must be 19,000 ft. (5800 m) or less on 26-gauge wire.

These lines are supported by the OPS line card.

• Control Over Voice (COV) Lines provide an interface for voice mail systems. The max-

imum loop resistance on a COV line must be 280 ohms or less, and the loop length must

be 3300 ft. (1000 meters) or less on 26-gauge wire.

These lines are supported by the COV line card.

Trunks

The system can connect to the public switched network or to private networks over both digital

and analog trunks.

The following digital links are supported:

• DS1 Links: The system supports CO, DID, E&M, MSDN/DPNSS, and MSAN/APNSS

protocols.

The SX-2000 LIGHT system connects to DS1 links by using a DS1 Formatter or DS1/T1

Formatter II card.