A T1 port is something that a T1 line hooks up to in order to establish the direct connection from the internet service provider's servers to your office or workplace. They are capable of handling up to 1.536 Mbps of upload and download bandwidth at one time, the speed of a T1 connection. T1 routers usually include at least 2 T1 ports, however some higher-end models will support up to 30 T1 ports.
Multiple T1 ports are more redundant and provide more reliability than one port. This is because the connection can be split up into multiple individual cables, so if one port goes down, the others will still be able to function. Also, if multiple T1 connections are hooked up at the same office or business, several T1 ports will be needed to support the T1 connections.
For a small business, only a 2 or a 4 port T1 router is usually needed. This is because most small businesses have only one T1 connection to the office, so two or four should be enough for multiple T1 lines and future expandability. A medium-sized business or organization might have a couple of T1 lines connected, so an 8 or 16 port T1 router should be sufficient.
If you need redundancy in the event that one or two of your ports go down, there is space for many more T1 lines to be connected. Large businesses typically use high-end T1 routers having 24 T1 ports or more, more than enough for 10 or more T1 links at a time. This may be needed if bandwidth is often saturated most of the time.
There are some accessories for a T1 port that may be useful when setting up a T1 router. A T1 port networking extender or repeater, usually coming with 4 or 8 ports, extends the number of T1 ports that your router can support. This is necessary to buy if you have used up all your ports and need more for business use. With multiple T1 ports, there is an advantage as they can be used together to give increased bandwidth.
Port scanners can also be very useful in seeing which ports are open or closed at the time on the T1 connection. The type of cable you use for your T1 line can also determine the speed and reliability of the connection at times, so make sure that you are using a high-quality cable for connecting to the T1 port(s).