how can we increase the sleeping time of a XBEE pro

for an XBEEpro 802.15.4 the sleeping cycle is 268 seconds maximum (cyclic sleep period ) SP in hexa : 68B0
is there is any trick to increase this time ?
on the 868Mhz it goes up to 1 hour !
thank you for help

The quick answer is that the 802.15.4 module uses a different processor and different standards. There is no way to increase the cyclic sleep period.

An alternative is to use pin sleep. See details in the user manual at http://ftp1.digi.com/support/documentation/90000982_M.pdf.