Stationary (landline, home) telephones for their intended purpose are currently being used less and less, giving way to mobile devices based on radio communications. Since the latter in most tariffs does not need to pay a monthly subscription fee, the cost of their use is even lower than that of stationary counterparts. At first glance, it might seem that when using wired phones, no questions can arise, since the technology is old and studied. But this is true for the developer, and not for the simple user of such a phone.
For example, sometimes companies and banking institutions indicate in their contact details a toll-free phone number, by calling which you can solve many issues. Usually on the other side of the wire, the answering machine picks up the phone, during the conversation asking the subscriber to press certain numbers (turn the dial). Alas, for many, the call ends here, as the answering machine does not react to actions with the phone in any way, ignoring button presses. Why?
The reason is simple - there is a pulse and tone mode of the phone. Surely, everyone heard strange clicks or beeps accompanying pressing numbers or dialing a number using the disk. Beeps are tone mode, and clicks are pulse mode. Consider how dialing occurs in old disk phones.
When the disk is rotated to the desired distance and it is automatically returned to its original position, special electrical contacts are closed: each closure forms a click-pulse, counting their number, you can determine the dialed number and, accordingly, the number. This “calculation” is carried out by the equipment at the station (ATS). Simple and effective. In newer phone models, the contacts are replaced by a special pulse generator, which, by the way, can also be switched to tone mode.
Subsequently, pulse dialing was replaced by a more technologically advanced tonal (tone). In it, dialing is carried out not by discharges, but by modulating the alternating current with the desired frequency. Each digit (button) has its own signal tone. Further, everything is similar: the PBX perceives a combination of tones and converts them into a dialed telephone number. Tone mode is more noise-resistant (errors in dialing now completely depend on the care of the owner, and not on the network status), and also allows you to more quickly connect to the subscriber. All modern phones are tonal, the pulse mode in them may be completely absent.
By the way, it is believed that the tonal mode provides higher sound quality. This is only half true. To work in tone mode, both the telephone and the telephone exchange must support it. Trying to use a new phone on a pulse exchange will not give any advantages (if, at all, the device will work). Stations calculated for the tone mode are digital (or mixed), unlike analog pulse ones. Hence the sound improvement.
A programmable pulse generator allows you to put the phone in tone mode and work both pulse and tone communication networks. Suppose that the subscriber is served by an analog exchange. To put the phone into pulse dialing mode, you usually need to press and hold the * button (asterisk) for several seconds. If this does not help, then we turn the device over and study the bottom cover - often there is a small toggle switch for choosing a mode. Switching to tone dialing is performed similarly.
Now back to the example at the beginning of the article. Owners of disk phones connected to analogue stations can forget about communicating with an answering machine requiring pressing any buttons, since this is impossible without additional equipment. Of course, there is a way out - this is a special prefix that generates tones in the network, but you will have to forget about convenience.