[ntp:questions] SNTP server + ntpd 4.2.4 client

Andy Helten andy.helten at dot21rts.com
Tue Mar 18 18:57:52 UTC 2008

I use PoE every day -- it powers the outdoor antennae that connects to
my wireless ISP (distance of about 5 miles).  I have gotten up to
3000kb/s over this link (which is slightly higher than what I'm paying
for).  So, whatever you are debating here, PoE is almost certainly *not*
the problem.

David Woolley wrote:
> Unruh wrote:
>> Just looked it up. A bit bizarre-- power over the ethernet? The ethernet
>> has no power supply capability. Do you mean that you have to supply the
>> device with 60V running on one of the unused ethernet cable lines? Sounds
>> noisy to me. 
> I believe it is a relatively new, but very real, standard.  The power is 
> transmitted as a phantom between two pairs.  In one variation, they are 
> the pairs used for normal, 10baseT.  I gather one reason is that there 
> are exemptions in electrical codes for ELV power feeds as part of 
> datacommunication systems, whereas a normal feed would require a 
> formally qualified (not just competent) electrician.
> The feed is 48V DC.  I'm not 100% sure that counts as ELV, but it is the 
> same as most analogue telephone systems.
> The apparent source specification is IEE 802.3-2005, although I haven't 
> gone to source.
> As the power is common mode with respect to the signals, the noise 
> should not be excessive.

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