The base came with a corded phone attached to it. Kind of pointless, since it wont work if there is no power to the base. Occasionally I end up using it though, since my parents [Mom] somehow manage to displace the downstairs handsets...
It also came with 5 cordless handsets - 2 black, 1 white, 1 blue, 1 red. Color coding helps keep track of the phones for us.
I'm pretty sure it's a 5.8ghz setup (says "Direct 6.0" on the phones).
However, all that crap above (for me) is worthless.
What matters is the batteries!!!
We've had a ton of different cordless phones in the past and they were ok but after a year they all had TERRIBLE battery life. The common theme was that they had NiCD (one had NiMH).
The ones we have now are Li-Ion, and have been going strong for at least a couple years now.
So you can do whatever you want regarding brand and operating frequency, but it's important to look at the batteries.
You have to bear in mind that only in the past few years Lithion Ion has been cost effective to be used in anything besides cellphones and it takes on a major price increase on the product. Till then, NiCad's and NimH were primarely used and you were lucky to get one year of good use out of them most of the time
We ditched a Sony cordless after 11yrs cause two or three buttons on the keypad stopped working consistently. After the 2nd NiCd batt pac cratered at less than 3months, I pulled one apart (replacement from Sony was ~$60) and realizing it was AA sized, I made my own using 3 2300mah Powerex rechargeables. That pac was still working when we upgraded to the Panasonic more than 9yrs later.
The Panasonic paperwork for the one we got goes on about how much more efficient they've made the device in the name of going green. It comes with Panasonic NiMh AAAs and after charging, I've not not seen any handset battery guage say anything other than full even after one of the wife's 2-3hr marathon gab sessions. The important thing batt wise is that its not NiCd, those don't work due to charge/discharge they see in use and their memory issue.