Network Object Reference

All exchange resources can be referenced either by directory numbers, or “physical numbers”. This is a challenge for the data protocol, as directory numbers can vary in size, and some resources have physical addresses with multiple parts. The NET_OBJ_REF is a “variant record” which has a header with byte count plus a type field. The rest of the information is then according to the type field and length. The total length can vary from 1 to 16 bytes.

NOTE:  AlphaCom 08.00 have a fixed size internally of 6 bytes for NET_OBJ_REF fields!

Format

<header> <contents….>

Where:

• <header> UINT1 defines both the length and the format:
  • <length> 4 bits. The length of the representation not including the first byte itself.
  • <format> 4 bits. The format of the representation. See the table below.
• <contents> See the table below.

Entity Classes

Used when referring to an intercom object with internal binary (“physical”) identification.

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Entity Subclasses

Used when very specific information is given, e.g. during error reporting. Subclasses are defined so that they can be used also for future exchange types working in AlphaNet.

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• Different Schemes should use non­overlapping value sets as long as there are enough available values --- Except for the NULL value that is shared by all schemes.
• NULL is represented by missing Entity SubClass field in NET_OBJ_REF value. The value 0 is reserved for representing this value in separate subclass variables internally in software.