asterisk users - Jun 2013 - recommendations for RJ-11 surge supressors?

I'd like to protect my expensive Digium FXO cards from spikes on my
three incoming PSTN lines.  Does anyone have any recommendations?

-- 
Eric Cooper             e c c @ c m u . e d u

On Thursday 27 June 2013, Eric Cooper wrote:
> I'd like to protect my expensive Digium FXO cards from spikes on my
> three incoming PSTN lines.  Does anyone have any recommendations?
Does your telco not fit surge suppressors to the NTE as a matter of standard 
practice?  Perhaps we are spoiled in the UK .....

-- 
AJS

Answers come *after* questions.