Slice of radio Tech question

i have a raspberry pi fitted with a slice or radio and also a Xino RF fitted with the same and they are talking together fine
now the tricky bit

i also have a RF Button that will transmit a 868.3Mhz 12 bit code (HT12/mm53200 type) on the press of a button

now i want the slice of Radio to see this button press and then when it sees it i can then do what i want it to do but first i need it to see the transmission

my question is How do i get it to see the 12 bit code
i see from the AT commends

Packet length
Requests / sets the maximum radio packet data length using an hexadecimal number between 1 – F0 (1 – 250 decimal) byties.
Factory Default is 0C (12 bytes)
Note: The SRF will not receive packets that are longer than this setting, so it needs to be set on all connected SRFs.

so in theory my slice of radio should see the button press but no led lights up when pressed