drpace wrote:If I bought a set for my home phone number and a set for home business phone number would there be interference between the two?
md1207 wrote:... I still have my 2.4Ghz, from years ago and they work well except my router interferes with them. ...
drpace,
you and md1207 both ask related questions.
The DECT system uses digital signals and encoding, which eliminates the kind of interference older analog cordless phones experienced. They also use a digital IDs to lock out handsets that are not part of the local, paired "network".
Just like WiFi network cards, every phone has a unique digital serial number. Each base unit is paired with the handset, and vice versa. Every data packet exchanged between the base and handset carries the phone ID and base ID. The base unit rejects signals from phones not paired with it, and handsets won't talk to base units they don't recognize.
That means you can have two separate lines to identical Vtech sets, and only the properly paired units will respond. Ditto, your neighbors can't eavesdrop, or steal free phone service.
With multiple, bi-directional communication channels, which also use time domain multiplexing to pack in lots of bandwidth, you can have dozens of phones in the same office without interference. I don't know what the upper limit is, but they use this same system for office PBXes with many dozens (hundreds?) of users.
And the DECT system uses 1900MHz (1.9GHz), not 2.4 GHz, so it avoids interference with 802.11B and G WiFi, bluetooth and is not affected by micowave ovens working around 2.3 GHz.
Plus the range is slightly better than 2.4 GHz with slightly better "penetration", since this is effectively a line-of-sight frequency, and attenuation goes up with increasing frequency.
See the Wikipedia article on DECT {Digital Enhanced Cordless Telecommunications) for more detail.