I have a customer with an NEC SV9100 (School) That get hit with Lightning 1 to 2 times a year which blows out (2) of the 16 port digital station cards that are connected to another building
The phone system was installed in 2015 (Spring)

They didn't start having problems until summer of 2017 (They got hit once knocked out (2) Station cards going to another building they also had some other computer devises get damaged

Then again in summer of 2018 (2) Times

Then yesterday in 2019

Keeps blowing out the same 2 cards (which causes the whole system to be flaky until you pull the cards out

There is Lightning protection on this 100 Pair cable which is grounded my question is how can I tell what kind of lightning protection is installed I am thinking its not for digital phones

I am assuming that its for analog its been installed for a while

it just says Lucent Technologies on the cover

looking for some suggestions


Thanks


JD