Building a Co-ordinated Dialing Plan (CDP).

When linking PBX's, dialing 4 digits to reach a four digit external extension can be set up using CDP. This will give the caller the impression that the call-destination is 'on-switch', or internal.

There's a clue in the name: Co-ordinated! A good understanding of the local dialing plan is essential. It may be necessary to make some changes to the dial-plan in order to free up digit blocks and construct a simple, logical dial plan between sites/PBX's. With 4 digit dialing, you can take 10 or 100 numbers out of the DN/DID block for off-sites. It may look something like this:

In the following example, the first digit dialed will be used to select the route (DSC - Distant Steering Code), and all of the dialed digits will be sent to line. The 'to line' digit string should be manipulated for the destination, not by the destination. It should be valid on the destination PBX. Calls to a vacant number (CTVN) will succumb to intercept treatment based on the route type (TIE?).

(Note, to allow DID to TIE connections: LD 15, NET_DATA, set DITI to YES)

Programming a CDB is a three step process:

First build (or modify) the ESN in LD 86 (NEW or CHG, FEAT = ESN) to set the 'Maximum number' parameters as required. Set NCDP to 4 for a 4 digit CDP dial pattern (max digits in CDP DN). Do not change AC1 and AC2 (hit return), or any other prompt unless necessary. Hit return until finished.

REQ  prt               LD 86
CUST 0
FEAT esn               Feature = ESN (Electronic switched network)

MXLC 100               Max # of Location Codes (NARS only)
MXSD 100                   '    Supplemental Digit restriction blocks
MXIX 100                   '    Incoming Trunk Group exclusion tables
MXDM 100                   '    Digit Manipulation tables
MXRL 100                   '    Route Lists
MXFC 100                   '    Free Calling area screening tables
MXFS 100                   '    Free Special number screening tables
MXSC 200               Max # of Steering Codes
NCDP 4                 # of digits in CDP DN (DSC + DN or LSC + DN)
AC1  9                 1 or 2 digit NARS/BARS Access Code 1
AC2  80                1 or 2 digit NARS Access Code 2
DLTN NO                Dial Tone after dialing AC1 or AC2
ERWT NO                Expensive Route Warning Tone
TODS 0  00  00  23  59
RTCL DIS    
NCOS 0 - 0
NCOS 1 - 0
NCOS 2 - 0
NCOS 3 - 0
:
:

Next, create a Route List Index (NEW or CHG, FEAT = RLB) in LD 86, pointing to the trunk route (ROUT).
Start from 10, as 0 thru 9 are generally reserved for BARS.

REQ  new               LD 86
CUST 0
FEAT rlb               Feature = RLB (Route list)
RLI  10                Route List Index to be accessed
ENTR 0                 Entry number for NARS/BARS Route list
LTER
ROUT 10                Use Route number
TOD
CNV
EXP
FRL  0                 Facility Restriction Level, 0 = no restriction
DMI                       
:                      Hit return until finished
:

Last, create the CDP (co-ordinated dialing plan) in LD 87 (NEW or CHG, FEAT = CDP, TYPE = DSC).
DSC - Distant Steering Code = access to remote code, or first digit of DN. Use the Route List (RLI) defined in LD 86.

REQ  prt               LD 87
CUST 0
FEAT cdp               Feature = CDP (Coordinated Dialing Plan)
TYPE dsc               Type of steering code (aaa = LSC, DSC, or TSC)
DSC
DSC  2                 Distant Steering Code 2
FLEN 4                 Flexible Length (0 = wait for interdigit-timeout)
DSP  DN                Display (LSC, LOC, or DN)
RRPA NO
RLI  10                Route List to be accessed for Distant Steering Code
NPA
NXX

Now, calls to 2XXX will go out on RLI 10/Route 10, and the digits 2XXX will be sent across the D-Channel.
If the DSC was set to 22, calls to 22XX would go out on RLI 10, and digits 22XX sent on the D-Channel.

Difference between DSC, LSC and TSC

DSC

Distant Steering Code: Sends call to a remote site through an RLI with all digits dialed. Make sure the ESN Data Block is set correctly. Example 72XXXX sends 72XXXX across the D-Channel to other site.

LSC

Local Steering Code: setup at local site will delete digits that are programed as LSC. In above example, would delete the 72 from the dialed number leaving the XXXX.

TSC

Trunk Steering Code: allows ACOD to be sent across the network to the remote site, giving access to the route with that ACOD. Example TSC X sends call to remote site where X is the ACOD for the RDB for outcalling.