Digit Manipulation
Digit abetment is the assignment of abacus or adding digits from the aboriginal dialed
number to board user dialing habits (for example, the addiction of prepending an area
code to a seven-digit punch string) or aperture needs. Chiffre abetment incorporates
adding, subtracting, and alteration blast numbers. For example, you ability charge to
add the breadth cipher to a alarm that will be baffled out to the PSTN or abolish a armpit code
from an intersite alarm with the aforementioned company. You can dispense alleged numbers, calling
numbers, and redirected numbers, as able-bodied as the cardinal type. You can administer chiffre manipulation
to admission or approachable calls or to all calls globally. You can dispense digits
before or afterwards analogous a punch peer.
Because the alarm abettor performs chiffre abetment in a Media Aperture Control Protocol
(MGCP) network, chiffre abetment ability be performed alone on H.323 and Session
Initiation Protocol (SIP) gateways.
Digit abetment is an important aspect of any punch plan, and assorted accoutrement abide on
Cisco IOS gateways to accomplish this task, including the following:
■ Basic chiffre manipulation: Chiffre abetment covers a spectrum of possibilities,
including prepending digits, stripping digits, or alteration specific digits. Examples
are
■ The digit-strip command is a dial-peer command that strips off the akin digits
in a destination arrangement of a punch peer. The digit-strip command is supported
on apparent old blast account (POTS) punch aeon only. Chiffre stripping occurs after
the outbound punch associate is akin and afore any digits are beatific out. The called
number is manipulated application chiffre stripping. Chiffre stripping is enabled by default
on POTS punch peers.
■ The forward-digits {num-digits | all | extra} command is a dial-peer command
that specifies how abounding akin digits should be forwarded. To specify which
digits to advanced for articulation calls, use the forward-digits command in dial-peer
configuration mode. To specify that any digits not analogous the destinationpattern
are not to be forwarded, use the no anatomy of this command. This command
applies alone to POTS punch peers. Forwarded digits are consistently right-justified
so that added arch digits are stripped. The destination-pattern includes both
explicit digits and wildcards if present. Chiffre forwarding occurs afterwards the outbound
dial associate is akin and afore any digits are beatific out. The alleged number
is manipulated application chiffre forwarding.
■ The prefix command is a dial-peer command that prefixes the defined digits to
the cardinal forwarded by the punch peer. Use this command to specify a prefix for
a specific punch peer. When an approachable alarm is accomplished to this punch peer, the prefix
string amount is beatific to the telephony interface first, afore the blast number,
associated with the punch peer. If you appetite to configure altered prefixes for
dialed numbers on the aforementioned interface, you charge to configure altered punch peers.
This command is applicative alone to POTS punch peers. This command additionally applies
to off-ramp store-and-forward fax functions. Chiffre prefixing occurs afterwards the outbound
dial associate is akin and afore any digits are beatific out. The alleged number
is manipulated application chiffre prefixing.
■ The num-exp command is a all-around command that applies to all calls and performs
a match-and-replace operation to aerate or collapse numbers. This command
is about acclimated for abbreviate dials and armpit codes. Cardinal amplification occurs
prior to analogous a punch peer. The alleged cardinal is manipulated application number
expansion. For example, a four-digit cardinal could be acclimated by an agent to
call a co-worker. That four-digit cardinal could again be translated to that coworker’s
home buzz cardinal and forwarded out to the PSTN.
■ The clid command can be acclimated to adapt the calling band ID (also accepted as
Caller ID); for example, to bind addition ID information. CLID manipulation
occurs afterwards the outbound punch associate is akin and afore any digits are sent
out. The calling cardinal and name are manipulated application CLID manipulation.
■ Articulation adaptation rules and profiles: Articulation adaptation rules and profiles are the most
powerful Cisco IOS accoutrement you can use to accomplish chiffre manipulation. Application regular
expressions, a calculation plan, and Blazon of Cardinal (TON) matching, you can make
nearly any accessible modification. The alone check is the circuitous syntax. Thus,
voice adaptation rules are generally accumulated with simpler mechanisms.
The adjustment of operation in chiffre abetment follows the alarm through the gateway, as
shown in Figure 7-1. For entering POTS calls, rules configured on the articulation anchorage are
applied first, followed by the admission punch peer, and again the approachable punch peer. For
inbound Articulation over IP (VoIP) calls, all-around articulation adaptation profiles are activated first, followed
by the admission punch peer, and again the approachable punch peer. Note the num-exp
command is activated globally afore any dial-peer matching.
Chapter 7: Configuring Advanced Punch Plans 369
1. Entering Articulation Anchorage Digit
Manipulation
2. Cardinal Expansion
3. Match Entering Punch Peer
4. CLID
5. Articulation Adaptation Profile
1. Match Outbound Punch Peer
2. CLID
3. Articulation Adaptation Profile
1. Match Outbound Dial
Peer
2. Articulation Adaptation Profile
3. CLID
4. Chiffre Strip
5. Prefix
6. Advanced Digits
1. All-around Articulation Translation
Profiles
2. Cardinal Expansion
3. Match Entering Punch Peer
4. CLID
5. Articulation Adaptation Profile
POTS
POTS
VoIP
VoIP
Incoming Call
Figure 7-1 Chiffre Abetment Adjustment of Operations
When possible, you should use a distinct adjustment of accomplishing the appropriate digit
manipulations. For example, do not use both the forward-digits and the prefix commands
in a dial-peer configuration.
It is accessible to use all the chiffre abetment methods in a gateway. A distinct punch peer
can be configured with prefixes, articulation adaptation rules, and clid commands. A alarm can
be adapted by the articulation port, cardinal expansion, entering dial-peer, and outbound dialpeer
configuration commands in distinct or assorted gateways. Understanding the adjustment of
operation in chiffre abetment is important not alone for agreement and analysis purposes,
but additionally for acceptable in troubleshooting.