The ‘Hardware Compatibility’ list has checks for
AirLink FXT Series : Fastrack Xtend GPRS; Fastrack Xtend EDGE; Fastrack Xtend HSPA; Fastrack Xtend CDMA.
This is wrong, because the user does not have have the necessary access to the embedded module within the Fastrack.
Actually, I think the user probably does now have access to the necessary pins on the XTend (but not the Supreme or earlier) - via its new 10-pin microfit connector, as used by the backup battery accessory.
But this is not documented at all in the Fastrack XTend User Guide, and is not adequately documented in the battery accessory documentation to allow a user to apply this.
The Supreme (and earlier) don’t give access to the module’s VBATT at all.
I think it would also be worth having an application note that specifically discussed & illustrated the design of an external battery backup for an XTend