10+50 PABX Sequence Diagrams

These sequence diagrams were included with the documentation that came with the PABX. They originally came from training course materials created by the Southern Alberta Institute of Technology (SAIT). I found them to be quite useful with troubleshooting, and in understanding the system, so I scanned them, cleaned them up, organized them, and put them online. Given that I know of no other person with one of these systems, this exists here primarily for my own easy access.

Index

• 4.0 Extension to Extension Calls
  • 4.1 Seizure
  • 4.2 First step
  • 4.3 Called extension free
  • 4.4 Release
  • 4.5 Called extension engaged followed by intrusion
  • 4.6a Spare numbers: Caller dials 1 or a barred code
  • 4.6b Spare extension: 'W' strap out
  • 4.7a Forced release: Dial tone but fails to dial
  • 4.7b Forced release: End of extension to extension call, caller fails to hang up
  • 4.8 Linefinder safeguard
• 5.0 Call Transfer/Consultation
  • 5.1 Incoming exchange line call
  • 5.2 Attendant keys extension 21
  • 5.3 Called extension free
  • 5.4 Release
  • 5.5 Called extension engaged
  • 5.6 Attendant intrudes to speak to engaged extension
  • 5.7 Ring when free, attendant withdraws from keyed busy extension and leaves exchange line in a camped-on condition
  • 5.8 Spare numbers: Attendant keys spare extension
  • 5.9 Consultation Calls: Extension 21 talking to exchange line wishes to consult another extension and then return to exchange call
  • 5.10 Transfer call
  • 5.11 Attendant recall
• 6.0 Exchange Line
  • 6.1 Outgoing exchange line call
  • 6.2 Pulsing
• 8.1 Night Service
• 10.1 Extension or tie line to assistance circuit
• 12.1 Incoming tie line calls
• 13.1 Extension originated outgoing tie line calls

4.1-4.3

4.4

4.5

4.6a

4.6b

4.7a

4.7b

4.8

5.1-5.3

5.4

5.5

5.6

5.7

5.8

5.9

5.10

5.11

6.1-6.2

8.1

10.1

12.1

13.1