Expected Digits and Num Digits
The gateway settings Expected Digits and Num Digits work in tandem. Expected Digits tells CallManager how many digits you expect the calling user to be dialing. Num Digits tells CallManager how many of those digits are significant to selecting a destination.
Num Digits is the easier of these settings to explain. Its heritage is the trunk interfaces, where you can often predict which digits a connected network sends. On a trunk interface, these settings tell CallManager to expect to receive n digits, the last m of which are significant for routing purposes. For instance, the central office might provide seven digits as the called number, but because the first three digits are always the office code, you just want to use the last four digits to route the call. Configuring 7 for Expected Digits and 4 for Num Digits causes CallManager to ignore the first three digits sent by the central office. If your dial plan is reasonably simple, as is often the case if your enterprise is smaller than 1000 users, using Num Digits provides you a simple way to maintain a four- or five-digit dial plan for your internal phones. (If your enterprise needs to support a large number of users whose external numbers are connected to a large number of telephone exchanges, Num Digits is often not powerful enough to handle the routing of your inbound calls. The section “Extension Mapping from the Public to the Private Network” describes how you can use translation patterns to route your inbound calls.)
Although the Num Digits setting tells CallManager how many digits you want to keep, the Expected Digits setting tells CallManager how many digits the PSTN is going to send. When the gateway to which CallManager is connected uses enbloc dialing, the Expected Digits setting is superfluous; because the call setup attempt contains all of the digits the calling user dialed, CallManager can immediately use the Num Digits setting to extract the digits that you want to route with. Expected Digits is a setting applicable to gateways connected to CallManager by protocols that use overlapped dialing. In such instances, CallManager needs to know how many digits to collect before using the Num Digits setting to extract the digits you want to route with.
When you configure these settings for a station device, they behave identically to this setting on a trunk device. CallManager ignores the first few digits that the user dials and uses subsequent digits to route the call.
ccie-srst-gw#show controllers T1
T1 0/3/0 is up.
Applique type is Channelized T1
Cablelength is long 0db
No alarms detected.
alarm-trigger is not set
Soaking time: 3, Clearance time: 10
AIS State:Clear LOS State:Clear LOF State:Clear
Version info Firmware: 20080918, FPGA: 13, spm_count = 0
Framing is ESF, Line Code is B8ZS, Clock Source is Line.
CRC Threshold is 320. Reported from firmware is 320.
Data in current interval (90 seconds elapsed):
0 Line Code Violations, 0 Path Code Violations
25 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
25 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Total Data (last 24 hours)
7 Line Code Violations, 4 Path Code Violations,
23932 Slip Secs, 0 Fr Loss Secs, 2 Line Err Secs, 2 Degraded Mins,
23931 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 215 Unavail Secs
ccie-srst-gw#
ccie-srst-gw#show voice port summary
IN OUT
PORT CH SIG-TYPE ADMIN OPER STATUS STATUS EC
=============== == ============ ===== ==== ======== ======== ==
0/3/0:0 01 e&m-wnk up up seized seized y
0/3/0:0 02 e&m-wnk up dorm idle idle y