[asterisk-users] Why Aastra uses 48V whereas other IP Phones usemuch less, i.e. 5-12V

[Michelle Dupuis]

48VDC is a long time telco standard - and has become the Power over Ethernet
standard.
 
Keep in mind that 'electricity' isn't the measure - it's power.  Power is
not synonymous with voltage.
 
The formula V=IR (voltage equals current time resistance) points to a higher
voltage allowing lower current draw on the line (with the same resistance).
Think of the small gauge wires in CAT 5 cable; higher voltage allows the
thin cables.  This has nothing to do with voice quality.
 
MD

  _____  

From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Zeeshan
Zakaria
Sent: Wednesday, November 22, 2006 9:30 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] Why Aastra uses 48V whereas other IP Phones
usemuch less, i.e. 5-12V


Does it effect the performance/voice quality? Does this also mean that 48VDC
is using less electricity in an office than 5VDC IP Phones?

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