2. SCOPE

2.1 This standard contains voice transmission performance and compatibility
requirements for ISDN voice terminals intended for connection to a public
integrated services digital network (ISDN). The requirements are based upon
the characteristics of the evolving ISDN, including interworking connections to
the present telecommunications plant.

These requirements should ensure satisfactory voice service to the user in a
high percentage of installations, both initially and over some period of time,
as ISDN service becomes more ubiquitous and as changes occur in telephone
serving equipment. However, because of the wide range of central office
switching equipment, PBX equipment, customer apparatus, and loop plant used in
North America, conformity with this standard does not guarantee acceptable
performance under all possible operating conditions. In general, where two
levels of acceptability are specified (desirable and mandatory), compliance
with the criteria in the desirable category implies a higher probability of
acceptable performance or compatibility.

2.2 These requirements apply to terminals that encode and decode analog
signals in conformance with u -law (Ref A10). These requirements apply also
to a terminal connected to the integrated services compatible station (ICS)
interface of an integrated services PBX (ISPBX) as specified in TIA PN 1993,
ISPBX Loss Plan (Ref A11).

These requirements are not intended to describe specific requirements for the
following types of digital voice terminal equipment: ISDN terminal adapters,
ISDN cellular voice terminals, ISDN terminal speakerphones, and proprietary
digital telephones designed to be connected to systems whose loss plan is
different from TIA PN-1993.

2.3 An ISDN voice terminal complies with this standard if it meets these
requirements when manufactured and can be expected to continue to meet these
requirements when properly used and maintained.

2.4 This standard is limited to ISDN terminals employing a close-speaking
microphone and an earphone that permit a single user to carry on a two-way
real-time voice communication (handset type telephone). This standard is also
limited to terminals with linear (noncarbon) technology transmitters.

2.5 The standard is intended to be in conformity with Part 68 of the Federal
Communications Commission (FCC) Rules and Regulations (Ref A7), but is not
limited to the scope of those rules. In the event that Part 68 requirements
are more stringent than those contained in this standard, the provisions of
Part 68 apply.

2.6 The terminal will also be subject to the applicable environmental
conditions specified in EIA/TIA-571, Environmental Considerations for Telephone
Terminals, (Ref A12).

2.7 The standard does not contain safety requirements. Compliance with the
requirements of Safety Standards such as UL 1459, Standard for Telephone
Equipment (Ref A5) and CSA C22.2 No.225, Telecommunication Equipment (Ref. A6)
may be required in certain locations.