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I'm probably missing something obvious but I've found the 3rd edition study guide inconsistent when describing the max power levels at the IR for this band and I'm not sure which values to pay most attention to. I've checked the errata and nothing is mentioned.

In chapter 6 it mentions 50mW for the UNII low band, 250mW for the middle band and 1000mW for the high band. In chapter 8 it mentions 40, 160, 280 on page 307 for these bands.

To add to the confusion, 800mW is 29dBm but on page 309 when talking about the maximum PTP power 30dBm/1W is used.

Slightly related, I was pretty sure in Chapter 6 it mentions that the high band isn't used in 802.11a so only 8 non-overlapping channels are available for consumer devices but it mentions on page 305 that early access points only supported low and middle bands but now all three are supported with the high band typically used for long range PTP connections.

So for the purpose of the exam which values are considered "correct"? If I get asked a question on the number of 802.11a non overlapping channels, would 8 and 12 both be potential answers and if so which one is correct? Or am I just missing something obvious?

You may be getting confused with regulatory limits (read FCC, etc.) vs. IEEE standard limits. They are different, and you will want to know the limits set by both.

FCC limits are 50mW (lower) 250mW (middle) and 1000mW (upper)
IEEE limits are 40mW (lower) 200mW (middle) and 800mW (upper)

Remember that IEEE works WITHIN the regulatory limits, so if the numbers are ever different, the IEEE numbers will be more restrictive.

If you want to use IEEE standard equipment, you'll be limited to IEEE restrictions.

IEEE 802.11a supports the lower, middle, and upper UNII bands (each with four non-overlapping channels). Lower and middle are for indoors use, while upper is for outdoors use only. So, for consumer devices being used indoors, the effective number of non-overlapping channels available would be 8.

Please recheck pg 307. My guide does not state 40, 160, & 280.

Also, make sure you understand the different rules (1:1 rule vs. 3:1 rule) affecting point-to-multipoint (PtMP) and point-to-point (PtP) connections.

This can be a confusing topic, so re-read this chapter a couple times. Hope this helps.

You may be getting confused with regulatory limits (read FCC, etc.) vs. IEEE standard limits. They are different, and you will want to know the limits set by both.

FCC limits are 50mW (lower) 250mW (middle) and 1000mW (upper)
IEEE limits are 40mW (lower) 200mW (middle) and 800mW (upper)

Remember that IEEE works WITHIN the regulatory limits, so if the numbers are ever different, the IEEE numbers will be more restrictive.

If you want to use IEEE standard equipment, you'll be limited to IEEE restrictions.

IEEE 802.11a supports the lower, middle, and upper UNII bands (each with four non-overlapping channels). Lower and middle are for indoors use, while upper is for outdoors use only. So, for consumer devices being used indoors, the effective number of non-overlapping channels available would be 8.

Please recheck pg 307. My guide does not state 40, 160, & 280.

Also, make sure you understand the different rules (1:1 rule vs. 3:1 rule) affecting point-to-multipoint (PtMP) and point-to-point (PtP) connections.

This can be a confusing topic, so re-read this chapter a couple times. Hope this helps.

You may be getting confused with regulatory limits (read FCC, etc.) vs. IEEE standard limits. They are different, and you will want to know the limits set by both.

FCC limits are 50mW (lower) 250mW (middle) and 1000mW (upper)
IEEE limits are 40mW (lower) 200mW (middle) and 800mW (upper)

Remember that IEEE works WITHIN the regulatory limits, so if the numbers are ever different, the IEEE numbers will be more restrictive.

Thanks for the response, I'm pretty happy with the various concepts but was just getting tripped up with the numbers and wording of when the FCC or IEEE values are being used.

The last sentence above the bullet points on page 307 confused me since it talks about deriving the maximum for a PtMP link under FCC regulations but the second from last bullet point uses the IEEE limit then on page 309, the FCC limit is used on page 309 in similar circumstances when talking about PtP links.