As with any short answer the real answer is “it depends”. Any modern internal phone system has a dial plan and the default will certainly call 911 but you can

As with any short answer the real answer is “it depends”. Any modern internal phone system has a dial plan and the default will certainly call 911 but you can certainly change it. I used to work inside a call center where you had to dial 91 to get an outside line. You can imagine how many people accident dialed 911. Since we couldn’t muck with 911 we made outbound dialing straight from the sip client only and not through the handset and told people not to dial outbound to order lunch or whatever from the handset. We didn’t care about them ordering lunch just couldn’t muck with 911. But that being said I could have most certainly changed the dial plan instead and screwed with 911.