If you are exploring new voice or information system lines for your office, you may find yourself overwhelmed with many new terms. Many people, for example, are quickly confused by the names used for various types of voice cable. Most start with RJ and then have a number, such as 11 or 25 after them. This actually refers to the type of connector, or Registered Jack, being used. An RJ11 cable has jacks that allow the use of a single phone line. The wiring necessary for two lines was designated RJ14 while RJ 25 and RJ61 are for 3 and 4 lines, respectively. Another term sometimes associated with wiring is "plenum cable." This is cabling that is made of the appropriate plastics to be used in a building's plenum and must adhere to much stricter fire code requirements than those used in walls and floors, which is referred to as "riser" cabling.
Many wonder: if the RJ number refers to the jack, why is it used to describe cables that are often in bulk without any connectors at all? It is actually very simple. The different RJ numbers refer to connectors needed to run a certain amount of voice lines. Each additional line requires more wire inside the cable, so an RJ11 cable only was enough internal wiring to connect an RJ11 jack providing one voice line. You could connect that same single line jack to a cable able to support more lines, of course, and still get the full use of the jack. However, if you connect a three line connector (RJ25) to cabling labeled RJ11, you would only have the wires available to run the single line. In short, a voice cable that carries an RJ name is indicating the most advanced style of RJ connector that it can provide with full service.
Often, it is wise to use a higher line cable than you currently need to accommodate future upgrades. If you would like to learn more about a new voice network and phone system installation for your company, please contact us. Everyone at Voice & Data Technologies, Inc. looks forward to helping you.