devices that provide much more advanced ability to receive and send text messages. Some devices now enable the receipt and sending of e-mail as well as Internet access. Since some cellular telephones are equipped to handle the text messaging and e-mail as well, the lines between pager com- panies and other wireless service providers are blurring. 282 The Telecom Handbook CHAPTER 13 Telecommunications Systems (Equipment) Business Telephone Systems (PBX and Key Systems) Installation and Maintenance Companies The telephone system installation and maintenance companies in your area can be found in the yellow pages under Telephones. Sometimes these companies are called telephone system ven- dors. They used to be called interconnect companies although this term is now rarely heard. These companies developed start- ing in the 1970's when it first became legal to purchase a telephone system from an outside supplier rather than renting it from the local telephone company. Some telephone systems are installed and maintained by the same company that manufactures them. These installation arms of the manufacturers are often former interconnect companies who first sold, installed and maintained the products of the manu- facturer and were subsequently acquired. Other installation and maintenance companies are authorized distributors and carry the product line of one or more telephone system manufacturers. In either case, the services you can expect from a telephone instal- lation and maintenance company include the following: You can purchase a business telephone system from them (including the backroom equipment and the telephones). They will install the system. Installation includes pulling the cable in the walls; connecting the telephones to the cables; and connecting the control cabinet of the telephone system to the other ends of the cables and to the outside lines brought in from the local telephone and long distance company. They will also install the switchboard console, used as a central answering point. They may also 