Originally Posted by
Jim Becker
Mike, Carlos is correct that SS7 has been largely depreciated since it was developed for the old class 4 and class 5 network switches which in the current world have been replaced by soft switches and IP/SIP in the network core. "Circuits" are a thing of the past outside of legacy gear that may still exist in some "mom and pop" areas in the US and some countries elsewhere. "PSTN" runs largely on IP/SIP at this point beyond the local CO and any remaining copper lines to homes and businesses.
I just retired from 21 years in that ecosystem that dates back to ol' Alexander Graham Bell.
It doesn't matter what you call it, Jim, the international telephone network is going to have a control system that has all the functionality and security of SS7, and probably more. So for discussion we can use the functionality of SS7 and not be too far off. You still have to set up a call, report call progress indications, and tear down the call when it's complete.
But the control system used does not have anything to do with whether a fax is a secure way to send information between two doctors. I maintain that it's pretty hard to hack into a specific call unless you're part of the system.
I haven't looked it up, but I expect that fax over IP is handled by coding/decoding the fax modem at the end points and then sending the actual data across in IP packets. The alternative would be to carry the fax modem modulation over the network, which would require replicating a 64kbps circuit. If only the data is sent, that data could be encrypted, just like any other data. I don't know if fax over IP encrypts.
I think we agree that hacking into the telephone network and extracting one specific "circuit" is extremely difficult for an outside person and that the only reasonable way someone could get the data is to wiretap the access line.
Mike
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