dbuckley Posted August 29, 2006 Share Posted August 29, 2006 Are current telephone switchers UPSed? Its a legal requirement that you can continue to make 999 calls under power failure conditions, so there has to be some provision for continued operation when the lights are out. Small phone systems (like the 6x24 I've got here at home) typically are not UPS'd, they have a failover mode whereby if the switch loses power then the incoming lines are autoswitched to specific extensions by an opened relay. So without power I've got a specific phone that connects to the line, the other phones are all dead. Once you start getting to a serious size then yes. you need backup power. Given that the phone boys have been at this lark a lot longer than the data boys, they've got their act well sorted. All telecom stuff runs on -48VDC (as in minus with respect to ground, so it's positive ground), and 48V is 4 x 12V batteries. So open the door on a power supply for a PABX and you'll see a switch mode charger and a few big deep cycle batteries. Since voice is converging with data (VoIP phones) then these phones need power, and PoE it is, and so the phones and the network behind them will need to be UPS'd, but it'll be done the data boy's way, which uses UPS, rather than -48VDC. Most serious network kit has multiple power supplies, usually slot-in hot replacable, and you can get -48VDC versions of power packs for the network gear, so in a primarily telecom facility with just the odd router it can piggy-back onto the telecomms power... Link to comment Share on other sites More sharing options...
Wilf dLampy Posted August 29, 2006 Share Posted August 29, 2006 Plus I've never seen the need to UPS the workstation network switches. If the power fails so are all the workstations, unless everyone happens to have laptops. :)Ah, but there's the situation where "the boss" has a shiny laptop and works through power cuts and would complain if he couldn't surf in the dark :D Link to comment Share on other sites More sharing options...
dbuckley Posted August 29, 2006 Share Posted August 29, 2006 Plus I've never seen the need to UPS the workstation network switches. If the power fails so are all the workstationsUnless all the workstations (actually, make that entire floors) are on UPS power too, which isn't uncommon in some business sectors. Link to comment Share on other sites More sharing options...
booboo Posted August 29, 2006 Share Posted August 29, 2006 Plus I've never seen the need to UPS the workstation network switches. If the power fails so are all the workstationsUnless all the workstations (actually, make that entire floors) are on UPS power too, which isn't uncommon in some business sectors. This is fast becoming an IT thread... :blink: Having grown up in Africa, I'm a little paranoid about power cuts, brownouts & spikes. Reckon they'll be getting more common here in a few years. So have put the beast of a UPS into our server rack - powers the entire rack, WAN, ISDN, phone system, ethernet switch, servers and all, and combined that with a smaller one downstairs to power a couple of key wokstations & a printer. Gives us about 20 min should we need it (once, so far). Would like to have installed an appropriate genny, but don't think our current size warrants it. Boss wants me to hook one up to each of the fishtanks too... Link to comment Share on other sites More sharing options...
Wilf dLampy Posted August 30, 2006 Share Posted August 30, 2006 Boss wants me to hook one up to each of the fishtanks too...Well, it's easier than fitting one to each fish to keep them swimming in a blackout :blink: Link to comment Share on other sites More sharing options...
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