Say I have a PBX system and want to connect the outside line to another PBX unit (as an extension). And say I want to connect that to a larger PBX, etc...
So, assuming that 9 is the outside line selector at each level, it would look something like when you dial the number 555-1212:
Not on PBX: 555-1212
Top Level PBX: 9-555-1212
1st Nested PBX: 99-555-1212
2nd Nested PBX: 999-555-1212
3rd Nested PBX: 9999-555-1212
...and so on...
(the PSTN is hierarchical in structure so this doesn't seem that radical)
Would there be any complications in such a setup, where you just move up the stack at each level?
Note I am not asking about a VoIP or digital setup: just a regular analog system and analog phone. As such, there would no concept of a "dial plan" in this system. There is literally nothing like to configure.
Here is a forum that exemplifies exactly what I'm talking about: http://www.classicrotaryphones.com/forum/index.php?topic=16612.0