scope:

This standard is one of a series of interface compatibility specifications prepared by the Services, Architecture, and Signaling Interfaces Subcommittee of Committee Tl. The series provides technical requirements for the interfacing of cellular mobile carriers (CMCs), wireline exchange carriers (ECs), interexchange carriers (ICs), international carriers (INCs), and consolidated carriers in paired interface combinations.

This standard provides technical requirements for EC-to-IC calls using an Exchange-Interexchange (E-I) Interface that interconnects a switching system in the EC network with a switching system in the IC, INC, or consolidated carrier network. The interface is at a point of termination (POT) between the two switching systems.

Technical requirements for IC-to-EC calls are described in American National Standard for Telecommunications - Exchange-Interexchange Carrier Interfaces - Individual Channel Signaling Protocols, ANSI T1.104-1988.

In the remainder of this standard, unless otherwise noted, the term IC connotes IC, INC, or consolidated carrier.

This standard supersedes American National Standard T1.109-1988, in which the carrier access code was specified as 95O+WXXX where W = 0 or 1 and X = 0 to 9.

Purpose.

The purpose of this standard is to enable separate entities to provide interconnecting equipment that will operate compatibly Quantitative descriptions are provided in this standard of the specific characteristics of the interconnecting systems required to achieve this objective.

Application

Interface. This standard establishes the technical requirements of the interface

(1) That is located between a public switched EC network and an IC network

(2) That has the following characteristics:

(a) The connection between the POT and the first point of EC switching is on a trunksignaling basis.

(b) The carrier access code is 950+xXxX where X = 0 to 9.

(c) On EC-to-IC calls, the EC sends, when applicable, the carrier access code and calling line information to the IC at the times and in the order specified by the signaling protocol.

Compliance. Compliance with these requirements is intended to assure minimum acceptable compatibility, where compatible operation is the ability of an end user to establish, maintain, and disconnect a desired connection through the use of the two networks.

Interfaces Not Included. This standard does not specify all possible E-I interfaces. For example, this standard does not provide the technical requirements for E-I interfaces with either of the following sets of characteristics:

(1) An E-I switched access interface using trunk-type signaling where the IC access code is lo= or any subsequent carrier access code using a larger than 3-digit carrier identification code to access the same interface.

(2) An E-I switched access interface using line-type signaling between the IC and the first point of EC switching.

This standard also does not specify E-I interfaces such as common channel signaling, network management, and switched 56 kilobit per second digital interfaces, or exhaustive electrical signal and timing characteristics.

This standard does not include local interface specification exceptions that are mutually agreed 11 AMERICAN NATIONAL STANDARD T1.109-1990 to by the interfacing EC and IC in order to provide access with switching equipment that cannot practically be converted to conform with this standard.

Illustrative Calling User Dialing. This standard describes the E-I interface signaling sequence using illustrative calling user-to-EC dialing (Tables 1 and 2). Other EC calling user dialing sequences, and signaling sequences from other EC interfaces, may also produce the specified E-I interface signaling. The dialing sequences and EC handling of the dialed information are, therefore, only illustrations and are not complete descriptions of dialing plans or EC services. Furthermore, the inclusion of the calling user dialing in this standard does not standardize either the EC dialing plans or the services associated with EC call routing or handling of dialed information.

Illustrative Numeric Values. The assignment of specific numeric values to the codes within the various E-I interface signaling protocol fields is beyond the scope of this document. Some specific numeric codes are included in this document for illustrative purposes; however, no attempt has been made to include exhaustive lists.