In API mode, I have read online that the max data packet per wireless transmission is 256 bytes.
The data sheet indicates, by the 16-bit Length frame, that the max data packet could be 65535 bits or approx 8190 bytes.
The MTU of wireless networks is 2,312 bytes. This size includes the packet headers. The Wireless MTU is considerably larger than the Ethernet recommendation for wired networks, which is 1,500 bytes. However, this larger size is only practical for traffic traveing within the network.