Instruction manual

Features and Services
● Calls made to specified COs or seven-digit telephone numbers within the Home Number
Plan Area (Home Area Code). These calls are routed as specified in the Home Area Code
Exception Lists, or else via the Area Code Routing Table, or (by default if not otherwise
specified) the local CO facility.
● Calls made to Area Codes outside the Home Area Code, sometimes referred to as Foreign
Area Codes (FNPAs). The route selected depends on the type of call, as follows:
— FNPA special number calls (includes all “800,” “900,” and Telex 510, 610, 710, and 810
numbers). Each FNPA of the form N00 and N10 may be assigned to a routing pattern.
— FNPA calls made to numbers specified in the FNPA Exception List.
— All other FNPA calls.
ARS Flow Chart
Figure 2-8 provides a simplified ARS flow chart. Bracketed numbers (e.g., [401], [601]) provide a
link between ARS administrable action numbers and the associated item on the flow chart. Certain
readers may find this reference useful when reading the following description in association with the
System 25 Administration Manual. Administrable System, Station, Toll Allowed, and Trunk action
numbers are also noted where applicable.
The ARS feature is accessed when a user dials the ARS access code. As shown on Figure 2-8, the
number dialed is first checked against the Emergency Numbers List. This list consists of special
service code 911 and up to three customer-defined seven-digit numbers. If the number dialed
matches one of the numbers on the list, the call is immediately routed via the local CO facility. All
user call restrictions are disregarded.
If the number dialed is not on this list, a check is made to determine if the terminal is allowed to
originate outside calls. If the terminal is outward restricted, the caller receives Reorder Tone;
otherwise, the dialed number is checked against any toll restrictions that apply.
Terminals may be assigned a Toll Restriction Class (1–5) or be unrestricted (Class 0). Terminals
assigned Toll Restriction Class 1 have the most privileges of restricted terminals; those assigned
Class 5 have the least privileges. There are five associated Toll Call Allowed/Disallowed Lists (1-5)
in the system. Up to 164 3-digit CO codes, 6-digit Area Code plus CO codes, and 6-digit
international codes (consisting of 0 plus 5 international digits) may be divided among the five lists.
Domestic numbers dialed from voice terminals assigned Toll Restriction Class 1 are checked
against all five Toll Call Allowed (TCA) Lists; domestic numbers dialed from Class 2 terminals are
checked against TCA Lists 2–5; domestic numbers dialed from Class 3 terminals are checked
against TCA Lists 3–5; domestic numbers dialed from Class 4 terminals are checked against Lists 4
and 5; and numbers dialed from Class 5 terminals are checked against List 4 only. If a domestic
number dialed does not appear or if an international number does appear in a checked list, the user
receives Reorder Tone. Calls originated at unrestricted (Class 0) terminals are not checked.
2-58 November 1995