We have a Toshiba Strata CTX 670 (T1 PRI) system here. (While I hope to have a modern VoIP system in place next year, my boss loves the Strata, and admittedly, it's been rock-solid). So solid that in my 3 years here I never had to call for any service or support on it…

Today we had an instance where for half an hour, we got barraged by dozens of spam calls. This brought up the question of whether and how we can block calls or numbers. I don't expect this 20yo system to have some fancy spam filters, but please tell me that there are some ways to filter/route/block incoming calls by phone number or, better yet, a range of numbers?

If you can point me in the right direction (like the name of the feature), I could figure out the rest in the various manuals, or engage a vendor. (If I can find anybody experienced in Strata's who's still in business.)

Thanks!