In the past, we would describe a Wi-Fi device by its capability. For example, we'd say this:
I have an 11a/g AP.
- Note: It has never been proper to say a/b/g. Why? 11g is always 11b. There is no such thing as an AP that supports 11g and not 11b.
Now I'm hearing this:
"I have an 11 a/b/g/n card". Or AP. Marketing departments like to say these things to make sure that the reader always knows it is backwards compatible.
All 802.11n is fully backwards compatible, with one exception, which is compatibility with 802.11a because it is 5GHz and 11n isn't required to support both bands.
So, here is the right way to say it.
"Single-band 11n" : This indicates that you have a device that supports 11b/g/n in the 2.4 GHz range.
"Dual-band 11n" : This indicated that you have a device that supports 11a/b/g/n in both 2.4 and 5 GHz ranges.
Ah, now I feel better. :)