You are in bathroom under the shower, and an important phone call comes your way, or even worse, you are in the final few minutes of preparing a delicious recipe and your spouse is on the line with an urgent message. What to do? A good cordless phone would solve your problems.
Cordless phones that are now in the market even come with multiple handset option, so that you can have one handset in your bathroom and another in your kitchen. You can also use your cordless as an intercom, or, in case of multiple handsets, as a walkie-talkie.
A cordless phone is basically a radio trans-receiver, and therefore the communication between the base-unit and the handset takes place in the radio frequency domain. The early cordless phones used the 43 MHz-50 MHz radio frequency band. Even today in India, good number of grey market brands, and also white market brands like BPL, Godrej, Crompton-Greaves, Beetel, Samay and Orpat, use the 43 MHz-50 MHz spectrum only, and unless one consciously asks for a 900 MHz / 2.4 GHz / 5.8 GHz cordless phone, 43 MHz-50MHz is what he is going to get!
There are number of problems with the 43 MHz-50 MHz cordless phones. They have interference and static from most domestic electrical appliances. The chance of evesdropping is very high with them. If your neighbour has the same brand of cordless phone, chances are that you would hear all his private conversations on your cordless, and vice-versa, and the situation gets even worse in crowded apartment complexes.
Sometimes you may hear police/army wireless transmissions on your cordless phone. The range of the 43-50 MHz cordless phones though is surprisingly decent contrary to the popular belief, but gets severely restricted if your house has metal sheet roofing (as is the case in Assam, a heavy rain-fall area, where I lived for six years). Though improvements to the 43 MHz-50 MHz phones came in the form of multiple line handling capacity, multi-channel transmission, digital encryptation to block evesdropping, better batteries, built-in answering machines, speaker phones, dual-dialing keypads, volume controls, etc., the fundamental flaws in these phones, namely poor voice clarity and electrostatic interference, could not be addressed.
Then came the 900 MHz cordless phones, first the analog ones (which again are prone to evesdropping), and then the digitally encrypted ones. 900 MHz phones avoid most of the pitfalls of the 43 MHz-50 MHz phones. But the problem is that the cellphones in most countries operate at this frequency, and therefore this frequency is inherently crowded. While the electrostatic interference is less, it is still not completely ruled out. Within a couple of years of the advent of 900 MHz phones, arrived the 2.4 GHz digital (or the 2400 MHz) phones, and these rule the roost in most of the developed countries today. A number of companies, including Sony, Panasonic, AT&T and Uniden, manufacture this type of cordless phones. The most recent development are the 5.8 GHz cordless phones, which are cutting-edge technology. The voice clarity of the 2.4 GHz and 5.8 GHz cordless phones is unsurpassed.
As far as the Indian brands are concerned, only BPL and Inditel (a Diu & Daman based brand) have released some decent 900 MHz models into the market. Recently, Uniden, a Texas based company, has entered the Indian market with a bang in the newly licenced 2.4 GHz frequency with digital models, and their phones have a number of features accompanied by attractive pricing.
I understand that 5.8 GHz phones are not released in India because the Indian Government has not yet given licences to cordless manufacturers to operate in this frequency (recall that using cordless phones in India required a special permission from the local telephone department even in the 1990's, and the Indian Telephone Act is of the 1880 era). But if you do get a digital 5.8 GHz cordless phone for home use, chances are that even in a ''tech city'' like Bangalore, you may not find another cordless phone operating in that frequency within 500 meter radius of your phone. Thus, the 5.8 GHz frequency as on date is totally unpopulated, and interference-free! If you live in an area where there is lots of wi-fi PC activity, or an intense use of closed-circuit cameras, or if you stay on hill-tops prone to lightning, or under high-voltage electric lines, 5.8 GHz is the only way.
By the laws of physics, cordless phones having lower operating frequencies should have higher range, all other things being equal. But this statement does not entirely reflect the truth. The range of a cordless phone is a function of its power-use. The existing norms in the manufacturing countries lay down that higher power-use(1W) is permissible in case of higher operating frequencies. Therefore, in practice, a 900 MHz phone can have up to 7-8 times more range than a 43-50 MHz cordless phone, and a 2.4 GHz phone can have upto 16 times more range than a 43-50 MHz phone. But please note, that range also depends upon the placement, the surroundings, and the weather.
If you are suspicious about evesdropping, look for a cordless phone that has a technology called ''spread-spectrum''. What this does is, even as your conversation is going on, it randomly changes the transmitted radio frequency from one channel to another within the operative frequency band, without effecting your conversation at all. No evesdropper would be able to intercept such transmissions, as evesdropping requires a fixed communication frequency to lock into.
The most popular cordless phone models include digital answering machines now. 15 minutes is usually adequate and some models have more available minutes. If you operate a home office, a 2-line model may be more apt for you. Those keen on the speaker-phone functionality, should buy one with full-duplex technology which allows both calling parties to hear each other while talking simultaneously. Half-duplex allows only one person to talk at a time, and their voice quality is poor.
All cordless phone handsets have a rechargeable battery, and the battery usually needs replacement after 1 to 1-1/2 years of use. Try to find a phone which uses a more advanced battery technology like Nickel-Metal Hydroxide instead of the run-of-the-mill Nickel-Cadmium, and also the one for which batteries are easily available. Dual-battery phones offer ultimate convenience and battery life, as one battery charges in the base while the other is used. Generally, the battery that is being charged in the base, also doubles up as a power back-up during power failures.
A dual keypad facilitates placing calls from the base as well as the hand-set, and thus, multi-party conversations. More the number of handsets, more can be the number of potential parties to conversations. A paging/intercom function would allow you to call the base from the handset and vice-versa, and from one handset to another handset. Paging can also be used to locate a misplaced handset by making it ring. There are also cordless phones amenable to the hearing impaired. These allow the use of ear-phones. Consider using them if you have a problem with your hearing.
The construction of a cordless phone needs to be rigid, and it should be able to take reasonable abuse, such as dropping by the children, and use in the bathrooms and kitchens. Instead of being an assemblage of several flimsy plastic pieces screwed into one, a cordless phone should be one single piece of good quality, shock resistant, molded plastic.
I hope this review is of some use to all those who are considering purchase of a new cordless phone. All the best!
