ATT DEFINITY Communications System Generic 3 Instructions Manual

							Automatic Route Selection (ARS)
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nSingle-stage dialing is supported for access to Feature
Group D, whereas access to Feature Groups A and B requires two-stage 
dialing. Two-stage dialing means that there is a pause for dial tone 
between the two groups of dialed digits.
nNo customer identification digits are required for access to Feature
Group D.
nA touch-tone telephone is required to enter a PIN code when accessing 
Feature Group A or B. A rotary or touch-tone telephone may be used with 
Feature Group D.
Digit Conversion
When the ARS access code and the called number are dialed, the d ialed 
number is compared to entries in the Matching Pattern fields of the ARS Digit 
Conversion Table sc reen. If all or part of the dialed number matches one of the 
Matching Patterns on the form, the matching part of the d ialed number is 
replaced by a new number from the “Replace” field on the form. This new 
number is then used to route the call. The new numb er will route the call via AAR 
over a private network. If no corresp onding entry is found in the AAR Digit 
Analysis table, the ARS Digit Analysis table is searched for a match with the new 
modified number and routed accordingly. (An intercept tone is supplied if a 
match is not found and the call fails.)
In G3r, digit analysis precedes toll analysis. Digit analysis implies both route and 
conversion. The algorithm for d eciding how to analyze a call is as follows:
nnumber of digits
nmost digits matched
nexplicit digits over wildcards (from left to right)
nconversion nodes over route nodes
The dialed number is compared with digit string entries on the ‘System’s Toll 
Analysis’ form for a relationship with the system’s Restricte d Call List or 
Unrestricted Call List.  If the dialed number matches a number assigned to a 
Restricted Call List, the call may not be allowed to complete. Also, if the user is 
toll restricted and the dialed number matches a numb er on the Toll List, the call 
may not be allowed to complete. Calls that are not allowed to complete receive 
intercept treatment when allowed by the unrestricted call list.
The primary purpose of ARS digit conversion is to convert public network 
numbers (to be routed with ARS) to private network numbers (to be routed with 
AAR).
NOTE:
You can convert back to another AAS number or an extension, where the 
extension most likely is a UUP. 
						

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This can save toll charg es and allow users to route calls on the customer’s 
private network facilities. Also, unauthorized p ublic network c alls c an b e blocked 
and routed to an attendant or receive interc ept treatment via d i git conversion.
Table 3-12 shows several ARS Digit Conversion examples.
The following conditions are assumed for the examples: ARS Access Code = 9, 
AAR Access Code = 8, Home RNX (Private Network Office Code) = 222, Prefix 1 
is required on all long-distance DDD calls, Dashes (-) shown in the ta ble are for 
readability only. (G3r analysis is more flexible because multiple conversions are 
permitted.) 
						

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NOTE:
The dialed digits are matched to the Matching Pattern that most c losely matches the 
dialed number.  For example, if the dialed string is 957-1234 and matching patterns 
Table 3-12. ARS Digit Conversion Examples
OperationActual Digits 
DialedMatching 
PatternReplacement
 StringModified
Address Notes
DDD call to ETN 9-1-303-538-1345 1-303-538 362 362-1345 The call will be 
routed via AAR on 
the route selected 
for RNX 362.
Long-distance call 
to presubscribed 
carrier9-10 22 2 102 22 + DDD (bl an k) ( b la nk) The  c al l wi ll  be  
routed as dialed 
with the DDD 
numb er over the 
c ustomer’s network 
facilities.
Terminatin g a 
loc al DDD call to 
an internal station1-201-957-5567 
or 957-55671-201-957-5 
or 
957-5222-5 222-5567. The call goes to the 
home RNX 222, 
Extension 5567
Unauthorized call 
to intercept 
treatment9-1-212-976-1616 1-XXX - 9 7 6 # ( b la n k ) The  ‘‘# ’’  s i g ni fie s  th e  
end of dialing.  Any 
d igits dialed after 
976 are ignored by 
ARS.  The user will 
rec eive intercept 
treatment.
International calls 
to an atten dant9-011-91-672530 011-91 222-0111# 222-0111 The call is routed to 
local switch (RNX 
222), then to the 
atten dant 
(222-0111).  This 
method may also 
b e used to block 
unauthorized IDDD 
c alls.  The call can 
b e routed to an 
announcement by 
replacing 0111 with 
an an no un c e men t 
extension.
International call 
from certain 
European 
countries 
ne e d in g   d ial  to ne  
detection0-00-XXXXXXXX 00 +00+ 00+XXXX The first 0 denotes 
ARS, the second 
p air of zeroes 
denotes an 
international c all, the 
p luses d enote 
‘‘wait,’’ for dial tone 
detection 
						

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957-1 and 957-123 are in the table, the match is on pattern 957-123. The call will  be 
routed as dialed.
Time of Day Routing
After an ARS call passes through ARS digit conversion (with no Matching Pattern 
found) and toll analysis allows the call, the Time of Day Plan Numb er of the 
calling party is used to make the choice of an associated ‘Time of Day Routing’ 
form.  On this form, a RPN is identified based on the time of day that is identified 
to the Partition Group Number. This plan is then used to select the specific 
partition of the ‘ARS Digit Analysis’ form, discussed later in this chapter, which 
will determine how the call is routed.
If Time of Day Routing is not assigned and  partitioning is enabled, the user’s 
PGN is used to select the specific ‘ARS Digit Analysis’ form.
See the AAR/ARS Partitioning and Time of Day Routin g features for more 
information. G3r searches analysis and conversion tables simultaneously.
ARS Digit Analysis
The following a p plies to G3vs/G3s, G3i, and G3i-Global. ARS calls that pass 
through ARS Digit Conversion, Toll Analysis, and Time of Day Routing, are 
analyzed based on the Time of Day Routing Plan Number or (if Time of Day 
Routing is not assigned) the user’s PGN.
The system uses ARS Digit Analysis to comp are the d ialed numb er with entries in 
an ARS Digit Analysis Table.  When the system finds a Dialed String entry in the 
table that matches the dialed number, the ARS Digit Analysis Table maps the 
dialed number to a specific Routing Pattern, discussed later in this chapter, and 
Call Type. The selected Routing Pattern will then be used to route the call. The 
ARS Digit Analysis Table screen also shows the minimum and maximum number 
of trailing d i gits required for digit analysis of each dialed number. G3r supports 
node number routing.
Possible Call Types in the ARS Digit Analysis Table are as follows:
n10-digit call within North America
n7-digit call within North America
nInternational call (in the United States, the international prefix
is 011)
nInternational operator
nO perator-assisted call (0+)
nService call (such as 811 for repair or 911 for emergency)
nNational numb ers within a country (used outside North America)
nUnknown call 
						

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Some special dialing p atterns are automatically mapped to a specific Routing 
Pattern and Call Typ e. They c an, however, be c hang ed by the system ad ministrator and 
probab ly will be c hang ed for PBXs used outsid e North Americ a. See 
DEFINITY 
Communic ations System Generic  3 Version 4 Implementation
, 555-230-655, o r DE FI NITY  
Communications System Generic 3 V2/V3 Implementation
, 555-230-653, for a list 
of these default translations.
Normally, the “Route Pat” (routing pattern) field on the ARS Digit Analysis Table 
screen contains a routing pattern numb er. However, this field may instead 
contain a Remote Home Num bering Plan Area (RHNPA) table number (r1 
through r32). An RHNP A is simply a concentrator for up to 1,000 calls. Calls are 
routed to these ta bles by ARS/AAR Digit Analysis when an ARS Digit Analysis 
table points to an RHNPA table. The next three dialed d i gits (the code) are 
compared with the codes in the selected RHNP A t a b l e.  Each c o de on the table 
is then ma p ped to a specific routing pattern numb er (one through 254).
The RHNPA tables allow up to 1000 c odes to be handled by one entry in the Digit 
Analysis ta ble.
In summary, Digit Analysis is merely a method of selecting a routing pattern. The 
routing p attern may be selected in two ways:
nIt may be selected directly from the Digit Analysis ta ble.
nThe Digit Analysis table may first have to select an RHNPA table which will 
in turn select the routing pattern.
Routing Patterns
The digit translations p erforme d on an ARS call b y the Digit Analysis and RHNPA 
tables cause a s pecific Routing Pattern to b e selected for the call. More than one 
combination of dialed digits can point to the same pattern. A blank entry instead 
of a Routing Pattern number provides intercept treatment. However, with ARS, 
d i git translation should always point to a Routing Pattern. This way, calls to 
unassigned office codes will b e intercepted by the central office, not by the 
system. By allowing the unassigned codes to be intercepted by the central 
office, the System Manager does not have to keep track of which office codes 
are in service. If calls to some codes are to b e denied, this should be handled by 
FRL assignment, not by intercept on the codes.  Facility Restriction Levels 
(FRLs) and Traveling Class Marks (TCMs) are discussed elsewhere in this 
chapter.
The R outing Pattern applicable for a given call contains a list of trunk  groups that 
can be used for the call. Trunk group access is controlled by FRLs. If access to 
the public network is through a main switch (an Ac cess trunk group is selected 
for the call), then the call will route through the main switch to one of the p u blic 
network offices serving the main switch. The d igit manipulation necessary to 
route the call is controlled by the Subnet Trunking feature. See the Subnet 
Trunking feature. Otherwise, the digit string to be outpulsed is controlled by 
ARS. ARS d igit manipulation is called  code conversion. Code conversion is used  
						

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to d etermine whether or not to outp ulse the d igit 1 on toll calls and whether to 
insert, keep, or delete the NPA on toll calls.
The following paragraphs describe how the switch decides what digits to 
outpulse in specific situations.
Digit 1 Outpulsing
The d i git 1 may or may not be required at the public network office to which the 
call will be routing. (If 1 is dialed on 7-digit calls at a stand-alone system 
(non-ETN), the 1 is outpulsed by the system.)  In the other cases, the 1 
outpulsing requirements are indicated in the system. Since any given call may 
have a choice of routes, some of which may require a 1 and some of which may 
not, this indication is associated with each route. Five choices are available and 
are identified in translations by a Prefix Mark. Digit 1 outpulsing only a p plies to 
calls administered as ‘‘fnpa’’ or ‘‘hnpa’’ in the ARS Digit Analysis table. The 
values and meanings of the Prefix Marks are as follows:
nPrefix Mark 0 — Suppress a user-dialed Prefix digit 1 for 10-digit FNPA 
calls, but leave a user-dialed Prefix digit 1 for the following types of calls:
— 10-digit calls that are not a dministered as FNPA or HNPA types in 
the ARS Routing Table.
— 7-digit HNPA calls
nPrefix Mark 1 — Send a 1 on 10-digit calls, but not on 7-digit calls.
nPrefix Mark 2 — Send a 1 on all toll calls (for examp le, all 10-d i git calls 
and 7-digit toll calls).
nPrefix Mark 3 — Send a 1 on all toll calls and keep or insert the NPA to 
ensure that all toll calls are 10-digit calls. Note that a user- dialed Prefix 
digit 1 for a 7-digit call makes it a toll call and, hence, NPA is also inserted 
in this case.
nPrefix Mark 4 — Always suppress a user-dialed Prefix d igit 1.
NOTE:
This capability is required, for example, when routing ISDN-PRI calls 
to an AT&T 4ESS. If the prefix digit 1 were not suppressed, then the 
4ESS would reach calls.
Which of the five possible treatments of the 1 prefix digit should be administered 
on a g iven route is based on the characteristics of the d istant office. Prefix Mark 0 
is prevents the system from sending a 1 prefix digit for 10-digit FNPA  calls. 
However, the system leaves a user-dialed prefix digit 1 for 7-digit HNPA calls 
and 10-digit calls that are not administered as FNPA or HNPA types in the ARS 
Routing Table.
Prefix Mark 1 causes the system to send a 1 prefix on all 10-digit FNPA  calls.
With Prefix Marks 2 and 3, the decision is based on whether the call is a toll call. 
Toll Lists are provid e d in the system to furnish this information. A Toll List sim ply  
						

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indicates if the office code associated with the call constitutes a toll call from the 
interconnecting office (not from the local system). Up to 32 Toll Lists are 
provided. The  applicable list num ber, if any, for the call is given in the Routing 
Pat te rn.
Prefix Marks are only applicable on 7- or 10-digit DDD public network calls. 
Requirements for outpulsing a 1 are specified via Prefix Marks and go into effect 
when the call accesses is outpulsed. Digit 1 outpulsing only applies to calls 
administered as ‘‘fnpa’’ or ‘‘hnpa’’ in the ARS Digit Analysis table.
NPA Deletion and Insertion
Each public network route in the ARS Routing Pattern contains an indication of 
the NPA of the distant end of the trunk group.  If this NPA is the same as the NPA 
associated with the call, the NPA is deleted prior to outpulsing unless the Prefix 
Mark is 3 and the call is a toll call in the associated Toll List.
NPA d eletion and insertion only a p plies to calls administered as ‘‘fnpa’’ or ‘‘hnpa’’ 
in the ARS Digit Analysis table.
The NPA is inserted on 7-digit calls if the distant NPA is different from the home 
NPA or if the Prefix Mark is 3 and the call is a toll call in the associated Toll List.
The preceding  paragraphs d escribe NPA deletion or insertion when the call is an 
ARS 7- or 10-digit DDD call. An ARS call accessing a tandem trunk is another 
example of NPA insertion.  If the call is a 7-digit ARS call, the system inserts the 
home NPA  before sending the call to the tandem trunk.  Therefore, all ARS calls 
accessing a tandem trunk are 10-digit calls. Whether or not the d i git 1 is sent on 
a tandem call is determined by the prefix rules. This enables the system to 
distinguish between ARS calls and the 7-digit on-network calls.
IDDD and Service Code Dialing
IDDD calls other than those using Subnet Trunking need not be mo dified before 
outpulsing. Since  international numbers can be of variable length, the system 
awaits a d ialing time-out before processing the call. The US ARS default dialing 
time-out is three seconds for the 0 and 1 prefix digits, but is 10 seconds for the 
called number. In other countries, the three se cond timer will ap ply to all 
numbers administered as valid dialed destinations that also happen to be 
sub-strings of a longer valid dialed destination. The calling party can sp eed up 
call processing by dialing the end-of-dialing digit # after the called numb er.  
Receipt of this digit cancels the remaining time-out interval.  The system always 
outpulses the # digit for use by the distant switch, whether dialed by the calling 
party or not (unless it is an ISDN trunk or it is su ppressed on the ‘Trunk’ form).
Subnet Trunking is not required for service codes. If the prefix digit 1 is dialed 
before the code, it is outpulsed.
ARS can provide individual Routing Patterns for each type of call. An ARS call 
can b e processed via the RHNPA table. This is particularly useful on international  
						

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calls, since the RHNPA table can be used on the country code.  Thus, call 
routing can be determined according to the called country, rather than handling 
all international calls alike.
Operator and Operator-Assisted Calls
Calls to an o perator (0 by itself) with 0 as the attendant access code, require a 
three-second time-out or dialing of the # digit before the call is processed. 
Operator-assisted calls (0 plus a 7- or 10-digit number) require 10-digit dialing if 
the call is within a home NPA and there are office codes within the home NPA 
which look like NPAs. (On directly dialed calls, this distinction was made by 
prefix digit 1 dialing.)  All other dialing is the same as direct dialing.
O perator-assisted calls, like IDDD calls, can be routed on the first three digits of 
the called number.  Through the use of Subnet Trunking, this means that different 
long-distance carriers can be selected for different calls.
These examples are for the US and will d iffer in other countries.
Considerations
ARS provides the most-preferred usage of public network facilities available at a 
system.
Routing Patterns, toll lists, and RHNPA ta bles are shared between partitions.
Internal memory resources  used for ARS Digit Analysis are shared b y Automatic 
Route Selection (ARS), Automatic Alternate Routing (AAR), Digit Conversion, 
and Toll Analysis features. A “ Percent Full” field on the ‘ARS’ and ‘AAR Digit 
Analysis’ sc reens indicate how many of these resources have been used.
If a customer changes ARS routing assignments, it is the customer’s 
responsibility to notify the RSC network designer and the SCO technician of the 
changes in order to receive their continued support.
Interactions
The following features interact with the Automatic Route Selection (ARS) feature.
nAAR 
ARS and AAR can access the same trunk groups and share the same 
Routing Patterns, toll lists, and RHNPA ta bles. ARS calls may be 
converted to AAR calls.
nARS
When an ISDN/BRI station dials sufficient digits to route a call, b ut could 
route differently if a dditional digits were dialed, the station will not 
recognize the Conference or Transfer buttons. The user must delay dialing  
						

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for three se conds or dial a # to indicate the call can be routed based on 
the digits already dialed. The Conference or Transfer b uttons are then 
recognized and the operation is completed by the switch.
nAbbreviated Dialing
FRL checking is bypassed on an ARS call made via a privileged 
Abbreviated Dialing Group List.
nAttendant Control of Trunk Group Access
Attendant control of a trunk group, in effect, removes the trunk group from 
the Routing Pattern.  The trunk group is never accessed by the Automatic 
Route Selection (ARS) feature.  ARS calls do not route to the attendant.
nCAS 
A CAS Attendant may extend a call out of a Branch PBX by use of ARS. 
The call is extended over an RLT by dialing the appropriate feature 
access code and number. The call is routed as determined by ARS 
administration at the Branch PBX.
nToll Restriction
Toll Restriction is checked on ARS calls.
nControlled Restriction, Origination Restriction, and Outward Restriction
These features prohibit access to the Automatic Route Selection (ARS) 
feature.
nForced Entry of Account Codes
Prefix marks and other digits inserted from routing patterns will not be 
used in determining whether a call is a toll call.   See  the  Forced Entry  of 
Account Codes feature for more information.
nGR S 
The Generalized Route Selection (GRS) feature works with ARS to 
provide call routing over the a ppropriate trunking facilities.  Routing is 
determined by the type of call being made.  With GRS, calls may be 
routed differently than they would with just ARS.  For details on GRS, see 
the Generalized Route Selection (GRS) feature description elsewhere in 
this chapter.
nMisc ellaneous Trunk Restrictions
Misc ellaneous Restrictions are not checked on ARS calls.
nPCOL 
A trunk assigned as a PCOL may not be assigned to any ARS routing 
pattern.
nRingback Queuin g
Ringback Queuing can be used on ARS calls originate d at the switch that 
provides the queuing.  Incoming tie trunk calls will not queue on an 
outgoing trunk group. 
						

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If a multi-appearance voice terminal user has an Automatic Callback 
button, makes an ARS call, and all trunks are busy, Ringback  Queuing  is 
activated automatically.
nCDR 
An ARS c all using a trunk group marked for CDR is indicated b y the d ialed 
access code and by a Condition Code. The dialed number is recorded as 
the called numb er.  Subnet Trunking does not affect CDR.
G3r can record outpulsed digits. If CDR generation is administered for a 
trunk group assigned to a Routing Pattern, data will be collected for all 
calls routed through the trunk group. If an CDR account c o de is to be 
dialed with an ARS call, it must be dialed before the ARS access code is 
dialed.
nVoice Terminal Display
The voice terminal display shows the dialed digits (not outpulsed d igits). 
The called-party shown on the display is that of the trunk group actually 
used. The “ Mis c ellaneous Call Id entification”  field on the display will show 
ARS.
An ISDN-BRI station may format these display fields differently, and the 
timing of disp lay u p dates may be different.
Administration
ARS is initially assigned on a per-system basis by an AT&T service technician. 
After the feature is activated, the following items are administered by either the 
System Manager or the service technician:
nARS Access Code 1 (one to three digits)
nARS Access Code 2 (one to three digits)
nARS Digit Analysis Table (1 per PGN)
nARS Digit Conversion Table
nUp to 32 RHNPA Tables
nUp to 32 Toll Lists
nFR L s  — Assigned via COR to each originating facility.
nUp to 254 ARS Routing Patterns
nTrunk Groups to be used with ARS
nWhether or not the system returns dial tone after the ARS FAC is dialed on 
trunk calls