hi
i would like to know the difference between analog and digital telephones

regards

A digital telephone typically is proprietary to a particular telephone system. An analog phone will plug directly into a POTS telephone line.

Digital telephones are connected to a digital LC NT8D02 and analog ones to NT8D09AK for example. what i mean is why they called it digital telephone? what is digital about it?

NT8D cards belong in a Nortel Option series PBX. Only a proprietary Nortel set will work on a NT8D02 but any standard analog set that would work at your house on your home line will work on the NT8D09. You may want to Google Digital VS. Analog to get the full idea of the deisgn.

Usually one pair of wires from a pbx sends dc voltage to run the digital phone and sends 1s and 0s to the phone which constructs voice and lastly 1s and 0s that tells the LED VM light to be on or not, which LCD by the button to be solid, which to be blinking, etc.

In essence, everything needed to run the digital phone is made of dc voltage and very high speed 1s and 0s.

An analog phone is simply dc voltage from the phone company (home phone) or from the pbx and voice transmitted without any use of 1 and o data.

Older electronic phones used two to four pairs of wire, often one pair being the analog voice, the second pair being the data to make the lights blink and power to run the phone on one wire of the first pair and one wire of the second pair. Many other combinations were used as manufacturers had different needs for their equipment.

No digital phone will work on an analog circuit, no analog phone will work on a digital circuit.