[VoIP] PC powersupply -48vdc suggestion

[Martin Harriss]

Richard Walsh wrote:
> I was looking to replace the power supply in my * PC with a substitute unit with a -48vdc input. I have an existing -48v plant for the PBX equipment.  This would eliminate the need for a separate UPS.
>    
>   I see many available power supplies from a google search, but does anyone that has been down this path know of a brand that has been reliable and affordable?  I am more comfortable getting a unit that others have utilized.  

I'd also be interested in hearing recommendations on this.  The PSU's 
like this that I've seen have all been quite expensive.

>   I was also hoping to take +12v out of the PC to power my DSL modem and my router/switch, both which presently have AC wallwarts with 12vdc outputs. I presume this is OK. The only hazard (perhaps a big one) is that the 12v rail is now powering a device that has some exposure to the DSL/POTS line (copper out to the street and beyond).

I doubt this would be a problem.  Both the phone line and Ethernet 
connections in the modem are isolated by transformers.  If you get a big 
enough lightning strike that it crosses the transformer, you've already 
lost.  If you'd like to feel a little safer, you could probably find a 
DC-DC converter to power the modem to give you a little more isolation.

Martin