[Gloucs] That SPA921 again !

[Graham Nye]

Andrew Oakley wrote:
> Geoff Bagley wrote:
> 
>> I do not understand the bit about  "ring capacitors".
> 
> AFAIK, a telephone line on its own does not generate a British ring. A 
> capacitor is required on a BT master socket, or is required on a master 
> adaptor for an RJ11 socket, to generate the ring.
> 
> I'm not sure whether this refers to "ring tone" (the buzz you hear when 
> you pick up the phone) or "ringing sound" (the alarm you hear when an 
> incomming call happens) though.
> 

The ring capacitor is required to make a phone ring
on an incoming call.  There is a wiring diagram at:
http://en.wikipedia.org/wiki/British_telephone_sockets

The tone you hear when you pick up the phone is
referred to as dial tone, as it indicates you can
now dial your wanted number. It doesn't use the ring
capacitor.

Note that this relates to an ordinary phone connected
to the public switched telephone network (PSTN) (e.g.
a standard BT telephone line).

It is completely irrelevant to a VoIP phone like the
Linksys SPA921.  This has an Ethernet connection to
your network. You can't connect it directly to your
BT telephone socket so no need to worry about ring
capacitors.



-- 
Graham Nye
glug at thenyes.org.uk