Help > Functions and applications > Exchange line routing
Exchange line routing
The exchange line routing adjusts the routing of incoming external calls (exchange line routing incoming) and of outgoing external calls (exchange line routing outgoing).
Exchange line routing incoming 
The exchange line routing incoming adjusts the call distribution. The call distribution defines the internal numbers to which incoming external calls are signalled, e.g. which internal phones ring when you receive a call.
For the number block of a system connection, linear call distribution always applies during initial setup. This means that external calls to individual DDIs are signalled to identical internal numbers. By adjusting the first internal destination, the internal destinations can be relocated into another area of the internal dial plan. For example: calls over the numbers 920010-920099 are signalled to the internal numbers 10-99. By adjusting the first destination to 210, the calls are signalled to the internal numbers 210-299.
Fallback destinations can be configured for non-existing internal destinations.
A number block can be separated as required by inserting a new number block for a partial area. This allows to separate the available phone numbers into differently treated areas. For example calls over the phone numbers 920010-920099 can be distributed to the internal number block 210-239 and 540-599. A new number block inserted for this purpose is always created with linear call distribution. The remaining number blocks keep their settings. If a number block is deleted, you will be asked which number block should be connected to. The settings of the chosen number block are adopted and any existing call forwardings are deleted.
*Further help under Internal numbers
In addition, external calls can here be directly forwarded to an external phone number.
Also individual external phone numbers are assigned to the Call Through function and remote programming.
*Further help under Call Through
*Further help under External access
Also block- and allowlists incoming are created here. These lists can be used to define individually for users and groups which callers are blocked (e.g. anonymous callers) and which callers are released despite Do-not-Disturb.
*Further help under Block- and allowlist
Exchange line routing outgoing 
The exchange line routing adjusts how outgoing external calls are handled depending on the dialled number. For this purpose, there are several routing rules summarized in one rule set. These rule sets are created to be used system-wide and are freely assigned to users, groups or special functions.
A routing rule defines how an individual phone number or a whole number range or phone number category is handled. The following phone number categories are part of each rule set: Emergency calls, International, National and City.
A routing rule defines which one of the available accounts (preferred) is used for initiating an outgoing external call. By selecting an individual account a preferred exchange line can be realised. Instead of calling an account, busy can be output and with this the exchange line authorisation be restricted.
In addition, a routing rule defines which phone number is presented. Using the CLIP no screening function (availability on the account provided) allows a free assignment of the phone number to be transferred independently from the used connection.
*Further help under Number presentation
For maximum availability, the routing rule for emergency calls can only be configured to a limited extent.
*Further help under Emergency calls
Also block- and allowlists outgoing are created here. These lists are assigned to the exchange line routing rule sets. Blocklists outgoing define which external phone number can be called. Allowlists outgoig define which external phone numbers differing from the routing rules can be called.
*Further help under Block- and allowlist
Configuration 
Setting call distribution.
Exchange lines > Exchange line routing > Exchange line routing incoming > Call distribution for
Creating new exchange line routing rule set.
Exchange lines > Exchange line routing > Exchange line routing outgoing > New
Configuring exchange line routing rule set.
Exchange lines > Exchange line routing > Exchange line routing outgoing >
Assigning exchange line routing rule set to a user.
User > Phone numbers > > Configure > Exchange line settings
Assigning exchange line routing rule set to a user configuration-dependent/time-controlled.
User > Profiles > > Exchange line settings
Assigning exchange line routing rule set to a group.
Groups > Phone numbers > > Exchange line settings
Assigning exchange line routing rule set to a group configuration-dependent/time-controlled.
Groups > Profiles > > Exchange line settings
Assigning exchange line routing rule set to the Call Through function.
Functions > Call Through > Exchange line settings