5.21.1.1. Summary 
Due to the great size of the number modification feature, the description
is preceded by a summary of the principles and rules.
The number modification has the task of modifying a phone number entered
as additional information ("calling number") in such a way that the dialing
of this number can always be interpreted by the system and a connection
established to the "calling number" at any time or place in the network.
There are two parallel methods for modifying the calling number:
Format-dependent number modification (AMO KNDEF, AMO KNPRE, AMO KNFOR)
For this modification method, you must do the following:
- Set the exit codes and prefixes to your own node (IDSN or PRIVATE) using AMO KNPRE.
- Set the codes (e.g. country code, area code, etc.) using AMO KNDEF.
- If destination nodes require certain formats, set them using AMO KNFOR (TONOUT).
- If a special display format is desired at your own node, configure it using AMO KNFOR (TONIN).
The most important rules:
- In each node that can be addressed with numbering plan NPI=ISDN or NPI=PRIVATE, all prefixes and exit code should be set up for the possible numbering plans using AMO KNPRE!
- All required numbering plans should be defined in AMO KNDEF. In case of CO lines, all E.164 entries are to be made here.
- The node format table (AMO KNFOR) should always be set up when external nodes require a certain format of the numbers or if the subscribers require a certain display format on their own node. If the KNFOR is not set up, the calling number will be by default displayed in the highest format (e.g. TON=INTERNAT) when outgoing and to the lowest possible format (e.g. TON=UNKNOWN) when incoming!
The source/destination-controlled modification (AMO KNMAT)
For this modification method, you must do the following:
- Using AMO KNMAT, set codes for certain source/destination combinations (virtual nodes). These codes should either be abbreviated from the calling number or placed before the calling number. If overlapping phone numbers are used, only the skip digits of the code to be supplemented or abbreviated should be entered.
The most important rules:
- By default, only the logical node numbers OWN and ROW should be used in AMO KNMAT for the UNKNOWN numbering plan. The following rule applies here: in ONNOL=ROW to DNNOL=OWN, the own node code is abbreviated when incoming and, in ONNOL=OWN to DNNOL=ROW, the own node code is supplemented when outgoing. For the own node code, a new logical value can be used. Using an "Supplement/abbreviate OWN with own node code of virtual code" entry automatically performs an implementation for all virtual nodes and extracts the code belonging to the virtual node from the AMO KNDEF table.
- By default, the AMO KNMAT should be used only for the UNKNOWN numbering plan (NPI parameter). The NPI=ISDN and NPI=PRIVATE numbering plans should be handled using format-dependent modification!
- When multi-level node numbers are used, the codes in AMO KNMAT must be entered at the corresponding level; that is, a country code (e.g. 49) is always at Level 2, an area code (e.g. 89) is always at Level 1, and a local destination code (e.g. 722) is always at Level 0.
- Modification conditions (the MODCON parameter in AMO KNMAT) must only be set for
multi-level networks in levels 1 and 2.
- For the ISDN or PRIVATE numbering plans, format-dependent number modification should always be configured.
- For the UNKNOWN OpenScape 4000 numbering plan (i.e. the selection of tie line codes), source/destination modification must continue to be configured.
- If configured, the source/destination-controlled modification always has priority over format-dependent number modification during execution.
General rules, regardless of the selected method of number modification
Regardless of the selected method of number modification, there are
a number of general rules stemming from the introduction of the new ISDN
and PRIVATE numbering plans or from the expansion from the one-level
to the three-level node number.
The most important of the general rules are as follows:
- If numbering plans not equal to NPI=UNKNOWN are used in a node, each route element (AMO LDAT) is to be assigned the respective numbering plan (NPI) and the type belonging to the destination number (TON) in the corresponding outdial rule (AMO LODR).
- Each node must be assigned a physical node number with AMO ZAND, parameter PNNO, and at least one virtual node number with AMO KNDEF. Each node number may be assigned only once in the network. Node number 0 is not valid.
- All OpenScape 4000/HiPath 4000 networks can continue to be operated with one-level node numbers. If multiple levels are desired, however, the node number ranges should be adapted to those of the phone numbers!
- When multi-level node numbers are used, all node numbers must be kept at the same level within the network! Even virtual and physical node numbers must have the same level.
Special rules for various connections
To connect multi-level subnets to one-level subnets and to connect
OpenScape 4000 systems to external systems, a number of special rules
must be observed:
- If, by way of exception, a multi-level subnet is connected to a subnet that is not on the same level, the COT parameter LWNC (line without node number) must be set in the respective set and a corresponding node number must be entered for this system in RICHT as the destination node. If the other system already has one-digit node numbers, LWNC must also be set there.
- Systems that do not understand node numbers should always be assigned COT parameter LWNC in the trunks leading to them.
- Lines that lead to external systems and that only transfer implicit phone numbers (for the definition, see Section 41.1.2.2, "Explicit and implicit phone numbers") must be provided with the COT parameter LINO. LINO may not be set for CO lines.
- The COT parameter DFNN causes the fictive, virtual node number assigned to the set to be used for modification. It prevents a reconstruction of the source node number and should thus be set only in exceptional cases.
This brief overview is intended to provide a general idea. The following
chapter, however, absolutely must be read and understood.