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Telephones are becoming electronic devices in much the same sense that computers are. They contain microprocessors and other electronic parts. New and more sophisticated features are being added, such as automatic dialers.

Here are important points to keep in mind when selecting phones and accessories:

Telephone companies require consumers to report their ringer equivalency number (REN). This REN is published on the instruction sheet or phone unit housing. Standard ATT phones have REN ratings of one. Compact, low-cost models may have as low as .7 REN or as high as 1.3 REN. If the REN on one line exceeds four, the phones will not ring.

There are three basic types of phones: rotary, pushbutton tone and dial pulse. The dial-pulse phone looks like a pushbutton tone, but its pushbuttons technically dial the phone. It doesn’t process a call as fast as the pushbutton tone.

Dial pulse gives the convenience of the pushbutton tone type of dialing without higher monthly cost. It should be noted too that pushbutton tone-type phones are required to access long-distance services.

Consumers should also be aware that installing a pushbutton tone phone means they must also be receiving this type service from the phone company.

Cordless telephone systems incorporate a base station connected to telephone line and a wireless handset. The distance a cordless phone will work away from the base station varies. It may be as little as 50′ or phones with antennas may work as far away as 1,000′.

Elevating the base station and placing it away from other reception barriers can improve cordless phone performance. One word of warning: In most cordless phones, ringers are located in the earpiece. The ring registers near 130 decibels, and if the phone is picked up and the switch not turned from “standby” to “talk” position, a phone ring could damage hearing.

Cordless phones are powered by rechargeable nickel-cadmium (nicad) batteries. The length of time required to recharge and the length of time between re-chargings seems to vary; it is necessary to read the instructions with the individual product to see how long the charge and how sensitive the battery is to frequent re-chargings. Some nicads will “remember” how much time elapsed between chargings and if they are recharged too often, will shorten the length of time they hold a charge.

Eventually the batteries will have to be replaced, but most phones will take several hundred chargings.


Accessories are available in either “conventional” or “modular” designs.

Installation of a conventional system requires no more than a screwdriver. Accessories are used in conjunction with standard telephones, using standard four-prong plug configuration, spade-tipped wires or hard wiring.

Plugs and jacks provide the connection for standard telephone and extension-cord hookups. They may also be attached to existing cords, adding versatility to existing phones.

No tools are needed for modular connections; the system was designed to allow “snap-fit” connection of miniature plugs with mating hardware. The following connections are available using the snap-fit modular concept:

Coil cords – old cords can be removed by depressing a clip and pulling the plug out of the phones base and handset. The new cord is then pushed into place until it locks.

Straight-line cords – plugs are clipped into the base of the phone and the wall receptacle.

Modular adapter – allows phones with modular line cords to be plugged into four-pronged conventional plug that matches the holes of conventional telephone jacks.

Modular plug and conventional jack – allows connection of conventional four-pronged plug extended line cords to modular jacks so that conventional phones can be plugged into modular connections.

Modular coupler – allows connection of modular plug-ended cords to each other for easy extension of phone system.

Duplex modular adapter – allows two modular extensions to be run off one modular unit. Used to connect telephone-answering devices.

Retrofit modular adapter – allows conventional telephones with spade-tipped conductors to be connected to modular jack assemblies without tools.

Surface wall-mount jack assembly – allows conversion of conventional terminal blocks to modular jack.

Portable wall-mount jack assembly – allows connection of modular plug-ended line cords in any location to convert four-hole jack to modular design.

Flush wall-mount jack assembly – allows flush-mounted connection of plug-ended modular line cords for initial installation or conversion from existing wall receptacles. Can be connected in parallel when more than one jack is required.

Wall-mount modular patio jack – weatherproof assembly accepts plug-end modular line cords.


Basic units require a tape recorder to handle incoming messages, as do some of the more expensive models. In most models, total answer time is limited, but more sophisticated units will allow for message of varying lengths.

There can be a hidden charge in these devices-some require the purchase of an Authorized Protective Connection Module which plugs into the telephone jack. The telephone company demands these if the recorder could produce excess voltage on the telephone line, thus damaging equipment or creating spurious signals.

Some models requiring APCMs include them and they add to the retail price. If units do not include APCMs, users will have to pay for installation as well as a monthly rental fee. Features which differentiate models include:

Leaving messages – some units permit the user to leave a tape-recorded message.

Dictation – some units double as dictating machines with no time limit on recording. A switch will stop and start the answer tape.

Announce only – for messages which require no response, announcements of when owner will return, for example.

Ring response adjustment – allows machine to wait to answer call until phone has rung up to 10 times. An advantage since it eliminates connecting and disconnecting unit each time owner leaves and returns.

Remote pickup – allows owner to pick up messages from a distance by telephoning the answering unit.

Extended recording – allows user to record a complete two-way conversation without being cut off after allotted message time.

Monitor – allows user to listen, undetected, to incoming messages as callers leave them. Listener can pick up phone and interrupt recording message if desired or simply let it be recorded.

Monitoring Receiving Frequencies
Low Band VHF, 30-50 MHz. Lowest and oldest of monitor bands. On this band a town or city may have almost any type of public safety activity police, fire, civil defense, etc. Frequencies can be received at greater distances.
High Band VHF, 150-174 MHz. Created to take the overflow from “low” band. Beside public safety, includes marine VHF radio and two-meter ham bands. User can be identified by 18″ antenna mounted on vehicle’s roof.
Low Band UHF, 450-470 MHz. Large number of police and fire frequencies. Antenna is a “toothpick,” about 4″ tall.
High Band UHF, 470-512 MHz. Has been created to take overflow from “low” band UHF.
Aircraft Band, 108-136 MHz. Not a major band. Used by aircraft communication over short distances, usually 200 miles and under. Considerable activity because of number of planes in flight.

Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.