Hello folks,

As you know, the 8012.11N standard allows using 2 channels of 20MHz bandwidth each ( Primary and Secondary) to double the wireless speed.

The knowing of the secondary channel number is very important in order to analyse a possible overlapping with other wireless signals whose the goal is to avoid interferences.

The secondary channel is automatically chosen with +4 or -4 depending on the limits by country.
That creates 2 possible modes called Lower and Upper
Lower means the Primary is below the Secondary
Upper means the Primary is above the Secondary

Example of Primary-Secondary in Europe for 2.4GHz:

Lower mode:
1-5
2-6
3-7
4-8
5-9
6-10
7-11
8-12
9-13
10-not possible
11-not possible
12-not possible
13-not possible

Upper mode:
1-not possible
2-not possible
3-not possible
4-not possible
5-1
6-2
7-3
8-4
9-5
10-6
11-7
12-8
13-9

Instead of that, TP-Link uses its own unique table, probably the following (I have not verified all the cases):
1-5
2-6
3-7
4-8
5-9
6-10
7-11
8-4
9-5
10-6
11-7
12-8
13-9

Questions to TP-Link:

1. Why the Secondary channel number is not displayed into the status page (there is only the Primary)?

2. Why the Upper and Lower mode is not implemented as it is with other manufacturers?

:eek: