Before the cell phone but way after smoke signals and Watson, there was the cordless telephone, a landline with a cord-free handset. Cordless phone communications are established over radio waves between the phone’s base station and the handset. Communications between the base station and handset is typically limited, with complete signal loss between the different floors of a house not unusual (or even from one end of an apartment to the other!). The base station itself is connected to a fixed telephone line like standard telephones. The base station is powered by mains electricity – that is to say, by electricity through a wall outlet. It is this base station, which is absolutely necessary, that continues to differentiate cordless phones from cell phones, despite the former’s much increased technological sophistication, such as cell handover technology, which allows for cell phone-like features such as data transfer and even international roaming.
But in the early days when cordless phones first appeared on the scene (it had been first proposed, actually, during the sixties, or two decades earlier), the devices were unreliable and very expensive. Not only was the operational range extremely limited and sound quality abysmal, but there was virtually no security or privacy because signals could be easily intercepted by other cordless phones in the vicinity due to the lack of channels available! It took just about a decade and a half for cordless telephones to at last gain the chance of being a common household item, thanks to the availability of greater frequency ranges, up to 900 megahertz, along with the introduction of DSS technology at year later, in 1995. These two technological innovations took care of eavesdropping concerns and cordless telephones were then free to take off as popular products. Though cell phones are everywhere and clearly going to be with us well into the future, many people still retain landlines in their homes for many reasons, and cordless telephones remain a viable product, with new models introduced fairly often.
When choosing cordless telephones, the number one thing that should be kept in mind is security: these phones are essentially radio transmitters and therefore susceptible to eavesdropping, though nowadays requiring a fairly high level of technical sophistication to do so successfully. In this respect, make sure to select DSS technology, at the 2.4 gigahertz frequency at a minimum (less is not as secure while more shortens battery life).
This brings us to the only other major issue: battery life. Avoid nickel-cadium if possible; they are subjected to a memory effect, which means that such batteries need to be thoroughly drained of power before a recharge. Other than these two matters, the rest of a cordless phone’s features are entirely up to personal preference.