Campbell RF401, Instruction Manual

Page: 63 / 130

C-1
Appendix C. Address and Address
Mask
Address
The address is 16 bits:
(0 - 1111,1111,1111,1111) binary
(0 - ffffh) hexadecimal
0 – 65535) decimal
The two parts of the address are the “Network Address” and the “Radio
Address.” The six most significant bits of the address are the “Network
Address”, and the ten least significant bits are the “Radio Address.”
Network Address Radio Address
(0 - 11,1111) (0 - 11,1111,1111) binary
(0 - 3fh) (0 - 3ffh) hexadecimal
(0 – 63) (0 – 1023) decimal
Address mask
The radio has a user programmable 16-bit address mask. Like the address, the
address mask is divided into two parts. The six most significant bits are the
Network Address Mask and the remaining ten bits are the Radio Address
Mask.
When an incoming packet header’s address is compared with the RF401’s
address, only the address bits that correspond to address mask “1”s are used in
the comparison.
Example 1
Incoming Packet’s Header Address xxxx xxxx xxxx xxxx
RF401’s Network Address Mask 1111 11
RF401’s Network Address yyyy yy
RF401’s Radio Address Mask 11 1111 1111
RF401’s Radio Address zz zzzz zzzz
Since the address mask is all “1”s, all of the incoming Packet Header Address
bits are compared against the corresponding radio’s address bits.
Example 2
Incoming Packet’s Header Address xxxx xxxx xxxx xxxx
RF401’s Network Address Mask 1111 11
RF401’s Network Address yyyy yy
RF401’s Radio Address Mask 11 1111 0000
RF401’s Radio Address zz zzzz zzzz
In this example, only the twelve most significant incoming Packet Header
Address bits are used in the comparison with the radio’s twelve most
significant address bits because the entire address mask (Radio Address Mask
appended to Network Address Mask) is 1111,1111,1111,0000. Since the last