Picture Perfect 4.6 User Manual - UTCFS Global Security Products

Chapter 8
Device management
135
12. A network dial-up micro must have a matching downstream micro.
13. A network micro must have a matching downstream micro.
Direct connect micros
A direct communications micro requires direct connection to the host. Communication can be unidirectional
as in Figure 55 or bi-directional as in Figure 56.
In uni-directional communication, each line of micros is connected to the host from a unique port (In
the example below, Micro 0 through 3 are connected to tty1; Micro 4 through 5 are connected to
tty2). If communication is lost between downstream micros, the host continues to communicate only
with those micros upstream from the break. An alarm is generated, indicating the loss of
communication. For example, if a break occurs between Micro 1 and 2, the host only has
communication with Micro 0 and 1 from tty1, and it maintains communication with Micro 4 and 5 from
tty2. Communication with Micro 2 and 3 is lost.
Figure 55.Example of direct communication - Uni-directional micros
In bi-directional communication, the micros are connected to the host using a primary port at one end
(tty1) and an alternate port at the other end (tty2). If communication is lost between any micros, the
host communicates from the primary port to all micros upstream from the break and from the
alternate port in the opposite direction, to all micros upstream from the break. Using this method,
communication with all micros is maintained. For example, if a break occurs between Micro 1 and 2,
the host communicates with Micro 0 and 1 from tty1, and it communicates with Micro 3 and 2 from
tty2. No communication is lost.