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.

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.