Feature interaction 7-15
Digital Switching Systems DMS-250 ISDN Reference Manual MWC14 (CSP14)
The onnet number is different from other dialed number types because of a
pretranslations table. This table identifies 3-digit codes as numbering plan
areas (NPA) or onnet office codes (NXX).
This means onnet NXXs and offnet NPAs cannot conflict within a given
pretranslator. The pretranslator used is determined on a per-call-type basis
and is datafilled in table CALLATTR. A pretranslator result of CT ONNET
indicates that the address digits apply to an onnet number. The pretranslator
result also indicates the minimum number of digits that should be received
in an incoming SETUP message. Failure to receive the minimum number of
digits results in PDIL treatment.
Public speed dialing—DDD/VNET
A public speed number allows the called number to be in an abbreviated
form. The called number used for routing is retrieved by means of a table
lookup. This table supplies a ten-digit DDD number or a seven-digit private
network number.
A pretranslations table distinguishes the public speed number (in the form
ZNXX) is distinguished from other forms of address digits. This table
identifies four-digit codes to be public speed numbers by using the CT
selector with the public speed (PUBSPD) call type. Translations occur as
follows:
• Search—When the number dialed corresponds to a public speed number,
the speed digits are searched for in the list of public speed numbers (one
of which may be associated with an originating partition).
• Successful location—If the speed number is successfully located in the
speed list, call processing replaces the digits dialed (with the digits from
the speed database). IEC translations are initialized again at that point,
beginning with digit interpretation and pretranslations. The speed list is
stored in table SPEEDTAB.
• Unsuccessful location—If the speed number is not located in the speed
list, vacant speed treatment is applied to the call. If public speed numbers
are not allowed on the originating partition, RODR treatment is applied
to the call.
• Treatment applied—In any case where treatment is applied to the call,
cause-to-treatment mapping may be applied as described in Chapter 5,
“Call control procedures.”
Ten-digit routing
Ten-digit routing allows a tandem switch to terminate calls. Tandem switch
termination avoids the access and egress charges that occur when the call is
routed by switches owned by local exchange carriers.
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