411, 611 & 325 OCU
User Manual
9
9M02-8999-A001-EN
This mode enables an OCU to simultaneously select between 1 and 8 MCUs (and r
equest a Talkback™ message
from any of those MCUs).
ESAC mode
= 8 bit Master Address and a 16 bit Sub Address where each bit of the sub address represents
one of 16 possible MCUs, this mode is only used in limited and controlled circumstances due to the reduction in
total effective telegram addresses.
e.g.
OCU Address = 0000 0001
1000 0000 0100 0101
MCU 1 Address =
0000 0001
0000 0000 0000 0001
(MCU Online matching MA plus SA bit)
MCU 2 Address = 0000 0001
0000 0000 0000 0100
(MCU Online matching MA plus SA bit)
MCU 5 Address =
0000 0001
0000 0000 0001 0000
(MCU Offline because there is no matching SA)
MCU 16 Address = 0000 0001
1000 0000 0000 0000
(MCU Online matching MA plus SA bit)
equivalent to a 9 bit address.
This is an extension of the BSAC mode that enables an OCU to simultaneously select between 1 and 16 MCUs
(and request a Talkback™ message from any of those MCUs).
4.2.2 CRC
The telegram is checked for integrity using a 16-bit CRC, corrupted frames will be rejected because the
recalculated CRC will not match the transmitted CRC.
4.2.3 Session and Frame Security
Each message is protected by an enhanced proprietary security protocol in such a way that every telegram sent is
both encrypted and unique, thereby eliminating any possibility of a ‘hacking’ or ‘store and replay’ attack from ever
being successful.
