Is there an error in the XBee-Pro 900HP manual?

Hi,

I’ve been working with the XBee-PRO 900HP’s recently, and I have noticed an error and/or contradiction in the datasheet.

On page 69 (RX Indicator API packet), there is a frame ID, and the “64 bit” source address is 56 bit. The frame ID is 0 in my observations, so does that mean that the frame ID was put into the datasheet in error?

How do I keep track of responses back and forth? Would it be best to incorporate some sort of tracking in the application’s packet header?