Omega Vehicle Security TCIC - Manual (Page 34)

TCIC User’s Manual
32
5. Multi-Card System
This section is relevant only for the TCIC with the RS485
communication option.
Introduction
The TCIC’s RS485 communication option supports multi-card
systems. In order to utilize this feature, two TCIC operations are
required:
• Card configuration
• Card selection
Card configuration – carried out by the TCIC-Monitor utility (see
section 3.2.2.4) – sets a card’s address to one of 26 options. This
address is saved in the card’s non-volatile memory ensuring that
once a card has been configured, the address is retained even if the
card is powered off.
Card selection – carried out by user’s application – activates the
communication with a card that has a specific address, and de-
activates (‘de-selects’) the communication with all other cards in the
system. Once a card is selected, regular communication can take
place, i.e. the card will respond to instructions from the main
command set. A selection lasts until an alternative address selection
is applied, or power is off. The Status LED (LED2) reflects whether
a card is selected or not: LED2 off means ‘card not selected’, LED2
on means ‘card selected’.
Addresses
There are 26 potential card addresses, denoted by the letters a,…,z
(lower case). Address ‘a’, the factory default, is unique in the sense
that its selection activates the card connected regardless of its
address configuration. Obviously, address ‘a’ should be used only
when a single card is connected. Otherwise all connected cards will
respond causing an RS485 bus conflict.