Eitsalo, It sounds like you are playing the cards dealt to you, and at this point, you need to produce/evaluate a scenario consisting of a backup to your PBX.
It sounds like you know "this is an exercise" - not one you would consider very valuable...but so be it...
What I'd propose as the plan might be this:
Today: You have a PBX and the likely disasters are "it stops working" The likely failures include:
- Physical damage to PBX room or portion of cable plant/closets... a backup PBX is prolly a 50-50 chance of being a solution.
- Power failure...(your power loss backup plan fails to work) then that strikes out a backup PBX.
- Telco failure... that strikes out the benefit of a standby PBX.
- PBX Hardware failure... a backup PBX sounds good here.
Of those 4 incidents, only the last one makes a backup PBX look good.
Let's say you implemented this: Subscribe to a Central Office based ACD queue with either digital or even analog lines placed at some or all stations.
Upon disaster you can do one of two things:
1- If the PBX is only down "partially" you can do a "dial-access activation" of Remote Call Forward of your main inbound DN to the CO Based queue telephone number and calls start hitting the backup phones.
2- If the PBX is trashed, you can perform a dial-access or 'call the carrier' activated redirect from the main inbound tele number to the backup queue's telephone number.
-In a power failure, the backup phones look perfect because they are line powered.
-In a hardware failure, you look good because people will then come to the realization that “it could have been any number of failures…”…many of which a backup PBX would not have been the solution.
My company’s main site has a “trading floor” equipped with an
Trading Turret system – it’s primary feed is from our Option 81C – but it also has a bunch of Centrex lines feeding it in case the PBX is lost. Then, we have a bunch of Centrex lines that go straight to 2500 (wall mount trimlines actually) as a backup in case the Turret system fails.
[highlight #CCFFFF]
[/highlight]