Inline power options for VOIP phones

You can buy a device designed specifically to sit between your regular, non IEEE 802.2af - compliant switch and supply power to a 802.3af - compliant terminal device, such as VoIP phone. They are called mid-span power supplies. PowerDsine makes those (as well as other people) and sells under OEM to lots of other (bigger name) manufacturers. They come in different port quantities between 1 and 24.

As far as costs are concerned, it has been a conventional wisdom that it is cheaper to have a UPS-protected mid-span power supply to send the inline power to the phones than to have a UPS installed at every phone location (and much more elegant if you ask me). However, with the prices of low-end UPSes falling, I'm not sure the common wisdom would survive scrutiny if someone was actually to look at the price difference. Besides, distributed UPSes help to get rid of the single point of failure problem. Anyways, I can buy a 350VA UPS that would power a VoIP phone for as much as 45 minutes to an hour for $35, and every IEEE 802.3af port (midspan or switch upgrade) costs on the order of $50. So, customer's convenience aside, I think remote UPSes may be a cheaper solution, and less prone to failure.

Depends on what you compare - chassis blades are a small uplift (most of the recent ones use a daughtercard on a non 802.3af module), but inline power is not available on the cheaper cisco stackable switches, so that could affect the relative cost.

Are there stand alone units installed

ignoring exactly which inline power system you use - you will still need a UPS on the ethernet switch and other central kit.

Cisco are starting to support 802.3af on their kit - but i am not sure if any of the phones have migrated yet - you need to check the spec.

last time i checked power dsine costs - a patch panel was about the same as buying a cisco inline power switch with the same number of ports. given that it sounds like you have to buy the switch anyway.....

an inline power switch is simpler since you avoid the wiring complications for the in span system,

standard practice is use a dual power switch, and use UPS on 1 feed, so loss of UPS doesnt kill the switch.

this tends to push you onto chassis switches with the cisco range (none of the stackables comes with dual power - you use an external dual feed power system) - Catalyst 4500s is the common choice for a chassis switch for a wiring closet.