XBee-Pro 900 (API): Retry Count does not change in TX Status (0x8B)

XBEE-PRO XB09-DP Firmware version 1002 Hardware version 1B42

The Retry count reported in a TX Status packet (0x8B) is always 3, unless the transmission is addressed to the sender, in which case the value is always zero. This is disappointing to me because I was hoping to detect a radio reaching a range limit by watching the reported retry count move away from zero.

Example: (addressed to the remote node)

Sent: 7E 00 19 10 05 00 13 A2 00 40 53 86 E2 AB AD 00 08 48 65 6C 6C 6F 20 77 6F 72 6C 64 9E
Rcvd: 7E 00 07 8B 05 FF FE 03 00 00 6F

Example: (addressed to myself)

Sent: 7E 00 19 10 06 00 13 A2 00 40 53 86 B4 AB AD 00 08 48 65 6C 6C 6F 20 77 6F 72 6C 64 CB
Rcvd: 7E 00 07 8B 06 FF FE 00 00 00 71
7E 00 17 90 00 13 A2 00 40 53 86 B4 FF FE 00 48 65 6C 6C 6F 20 77 6F 72 6C 64 B4

Note also that although there is a Delivery Status of 0x23 (self-addressed) possibility in the documentation, the Delivery Status = 0 here (= Success)

Also, the Discovery Status byte is always zero (No Discovery Overhead). I have not been able to create a case where this value is anything else.

This is the (prompt, BTW) response I got when I contacted Support for their assistance…

The Retries the API packet is referring to is related to the Mesh Retries and not an application level retry. Since being released, we have also located an issue with this where an incorrect value was report. This has since been addressed and should be corrected on the next version of the code.