RJ11 is the standard for a telephone jack in the US. Before cellular phones became commonplace, RJ11 was needed to give people a home phone. However, nowadays – most people have cellular phone lines, and no need for a copper line service. This means it becomes an unprofitable cost on Verizon to keep the copper line services running. With that being said, copper line phone service is very expensive, and no new customers will be accepted. In addition, if a customer was to move, they will lose their copper line phone service.
Because of this, there is really no need to install RJ11 connections, and this will be a waste of time, money, and resources. Why have an obsolete RJ11 jack when an RJ45 can do everything and more. Now, this leaves a question what about this device? Well, for the elevators, there will be a telephone line that will run from the elevator to the telephony server. The phone line will plug into the server, and provide VOIP services for both telephone lines. As for security systems, most of them went to using Wifi, or cellular for their connections. This eliminates that need. For the intercom system, there is a button that will buzz an intercom in the great room. If there was a need for a physical fax machine, that machine will plug into an ATA (Analog Telephone Adapter), and then plug into an RJ45 connection. All of these issues are now addressed, and while I have 2 remaining FXS ports, they will never be used.
If I need a desk phone for whatever the reason, I will acquire a SIP capable phone. This phone will plug into an RJ45 connection, and make calls through the telephony server. However, a more likely option will be to install a SIP client on the smart phone, and have 2 lines for the smart phone (one for the home, and one for the cellular). The idea is to reduce the dependance on RJ11, and if there was an elevator company that would allow me to plug in the network (RJ45) instead of using RJ11, then I will likely go with that company for my elevator. This will eliminate all of the RJ11 connections that will be otherwise needed.