Specifications

Chapter 1 Introduction Installation and Operation Manual
1-6 Applications HS-RN MP-2100/2104 Ver. 12.6, MP-4100 Ver. 2.0
Location B
Location A
Location C
HS-RN
(Bidirectional
Broadcast RX)
Port 1
Port 3
RX TX RX TX
Port 1
Port 3
Megaplex with
2 Main Links
HS-RN
(Bidirectional
Broadcast RX)
HS-RN
(Bidirectional)
Port 1
Port 2
Megaplex with
2 Main Links
HS-RN
(Bidirectional)
Port 1
Port 2
Megaplex with
2 Main Links
Location D
Figure 1-5. Typical Bidirectional Broadcast Application
The broadcast capability is achieved by separating the handling of the receive and
transmit paths for the timeslots assigned for the broadcast channels, as shown
by the dashed lines within the Megaplex units in
Figure 1-5.
The bidirectional broadcast mode is not available for the module operating in the
Megaplex-4100 chassis.
The user at the central location is configured to use the regular (bidirectional)
mode, and therefore it can both transmit and receive. The other users are
configured to use the bidirectional broadcast receive (BID BRD RX) mode: this
mode is similar to the unidirectional receive mode, except that at any time one of
these users (and only one) can transmit to (and be received by) user A. This
mode of operation is used in polled applications.
In the application shown in
Figure 1-5 , the handling of the signals generated by user
A is similar to that for the unidirectional transmit mode described above. The
difference is that each broadcast user can insert its signal in the receive timeslot that
reaches user A (instead of the signal bypassed from the other link). The change in
routing is controlled by the RTS signal in the data connector of the HS-RN module:
• When the RTS signal is not active (idle state), the receive timeslot is bypassed
from link B to link A, and continues toward user A.
• When the RTS signal is asserted, the receive timeslot of link B is disconnected
from link A, and the transmit path of the local broadcast user is connected to
link A.
Thus, user A can request any user to answer, and that user can assert its RTS line
and thus connect to user A. At any time, only one user may transmit toward user A
(if more than one user transmits, only the user closest to location A will actually be
received). When using the bidirectional broadcast receive mode, it is necessary to
instruct each main link port how to handle the traffic flow information. This is
performed by defining the timeslot type, as part of the DEF TS command (see
Megaplex-2100/2104 Installation and Operation Manual ).
Note