Mike's PBX Cookbook

New Flexible Code Restriction

NFCR controls the access of Toll Denied (TLD, CTD, CUN) stations and trunks to outgoing routes, based on the specific digit sequence dialed. This is useful for blocking certain digit strings (or area codes) when the route access code (ACOD) is used, assuming that TGAR has allowed access in the first place.

NFCR and Class of Service (CLS):

CTD, CUN NFCR restrictions do not apply for BARS, NARS, CDP or ANI type calls.
NFCR applies only on direct trunk access code (ACOD) type calls.
TLDUsers are always affected no matter how their call is dialed.

The FRL associated with the users NCOS is used to determine which codes are allowed or denied.
Stations are by default Conditionally Toll Denied (CTD). See also CLS Access Restrictions.

NFCR Implementation:

LD 21, print FCR (FCR_DATA) to see is NCFR is enabled (default is disabled) - change FCR in LD 15.

REQ: prt
TYPE: fcr_data
CUST 00 
NFCR YES                      New Flexible Code Restriction is enabled!
  MAXT 100                    max. number of code restriction trees (LD 49: CRNO)

LD 87, NCOS - FRL map, often 1:1.
The FRL normally controls access to an RLI entry: FRL 0 is the most restrictive, 7 is the least restrictive and can access more entries. For a toll denied set dialing an ACOD, with NFCR YES, the FRL controls which code restriction tree is referenced for route access.

REQ  prt
FEAT nctl
NRNG 0 10                     enter a from-to NCOS range to print
NCOS 0                        NCOS value...
FRL  0                        mapped to FRL value
NCOS 1                        NCOS value...
FRL  1                        mapped to FRL value

LD 16, in the Route Data Block, an NFCR tree number (CRNO) is assigned to each Facility Restriction Level (FRL).
Scroll down to the FRL section, near the bottom of the RDB block to see the CRNO assignments. Default is 0:

FRL  0 0                      sets with FRL 0 will reference CRNO 0 
FRL  1 1                       "    "   FRL 1  "       "     CRNO 1
FRL  2 2                       "    "   FRL 2  "       "     CRNO 2
FRL  3 0                       ... etc
FRL  4 0 
FRL  5 0 
FRL  6 0 
FRL  7 0 

Use LD 49 to administer, and print, code restriction trees and digit string (NFCR) data.

Any digit sequences is initially (INIT) ALOWed or DENYed
Exceptions can be: DENY / ALOW / or BYPS (exceptions make the rule!)

REQ  prt
TYPE fcr
CRNO  0                       code restriction tree number
INIT ALOW                     by default allow all codes
                              <- no exceptions
CRNO  1 
INIT DENY                     initially, deny all codes
ALOW 555                      <- exceptions, digit sequence to be allowed
INIT ALOW                     initially, allow all codes
DENY 1900                     <- exceptions, digit sequence to be denied

LD 49 is also used for Incoming Digit Conversion.

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