[snip]

UH Actually runs on a very high frequencey
No, lower prequency is correct Worldwide DECT standars is 1800/1900
mhz - North America is DECT6.0 - running at 1920/1930mhz.
Significantly lower frequency than the older common5.8ghz, but higher
than the old 900mhz

BTW, at one time 900MHz cordless phones were NEW. Most used 54MHz.
Also, there was no way to change the channel in case of interference.