There are multiple types of lines and also several technologies to consider. You can choose from local or long distance service, incoming or outgoing or bidirectional, and toll free line services. But you can also choose the connection technology. These include analog, switched circuit digital, and IP-based digital.
Analog telephone service has been the mainstay of telephony for over a century. It’s so mature and familiar that it’s known in the industry as POTS or Plain Old Telephone Service. POTS connects by a single copper twisted pair directly from your location to the telco central office. It uses a combination of DC and AC voltages to give you dial tone, rotary and touch-tone dialing, full duplex conversations, and on-off hook signaling. POTS also supports Caller ID.
One POTS line supports one telephone conversation, but it can support more than one telephone set. A very common arrangement is 2 to 4 POTS lines connected to a 2 or 4 line business phone. Multiple phones can make use of these lines, but you need to look for a line-in-use light to know if a phone line is free for your use. When you expand to 4 to 8 lines, you’ll probably install a key telephone system that allows the various phone sets to communicate internally without using an outside line. This system still uses indicator lights to show which lines are in use. You have to manually select an available line to make a call.
PBX systems are computer-based telephone controllers that take over the job of managing outside phone lines. You can connect as many POTS lines as you need to the PBX. When someone requests an outside line by dialing “9”, the system will use the next available line. Users don’t have to worry about selecting lines themselves.
PBX systems also offer a way to reduce your telephone service costs by using digital trunking services instead of POTS. You need 6 to 12 outside lines at a minimum for this to be cost effective. Instead of installing a dozen POTS lines to your PBX system, you plug in a single T1 telephone line that supports up to two dozen phone lines on a single “trunk” line.
The most popular switched-circuit telephone trunk that replaces multiple POTS lines is called ISDN PRI. ISDN is a digital telephony standard, PRI stands for Primary Rate Interface. This service is delivered over a T1 line, so it is also called T1 PRI. What you get is up to 23 outside lines that you can specify to be incoming, outgoing, local, long distance, etc. There is also a signaling and data channel that provides rapid connections and Caller ID services for each line.
A recently developed service called SIP Trunking is based on IP networks used for converged voice and data services. A SIP Trunk can carry both broadband Internet and VoIP telephone services between your location and your service provider. SIP trunks may have a cost advantage, especially if you can use a single T1 line for both voice and data.
Interestingly, both traditional PBX systems and the newer IP PBX systems can connect to POTS, ISDN PRI or SIP Trunks. You need the appropriate interface card, of course, but many systems offer multiple interfaces built-in. If you need more lines, you add one or more additional interface cards.
With all these options, what is the most cost effective solution for your business telephone needs? The best solution will be based on your specific usage patterns and the latest offers from multiple competitive carriers. That’s too much information to digest by simply shopping around. A better way is to use a combination of an automated search process and expert consultants. Both are available for your use at no cost at T1 Rex. Use the online GeoQuote (tm) or call the toll free number for immediate service, and see how much you can save compared to what your phone services currently cost.
