Comtech EF Data MIDAS 4 System and Design - Manual (Page 57)

System and Design Manual, Revision 2
Theory of Operation 3–15
The MIDAS Controller could initiate the establishment of a point-to-
multipoint simplex data circuit due to the activation of a pre-defined point-to-
multipoint circuit by the MIDAS operator. A typical MIDAS Controller
initiated point-to-multipoint circuit setup proceeds as follows:
1. The MIDAS operator defines a point-to-multipoint circuit by specifying
the transmitting traffic channel, the receiving traffic channels, data rate,
encoding, modulation scheme, etc., and activates it, or activates a pre-
defined circuit by specifying the circuit ID.
• For a point-to-multipoint circuit utilizing Comtech EF Data CiM
Modems, the CiM Modems require (predefined) route table entries.
2. If the required resources are available, the MIDAS Controller allocates
bandwidth and sends an assignment message to all the participating traffic
nodes.
3. The Node Control Modem at the transmitting traffic node configures the
traffic modem and enables the transmit. It also responds with a status
message indicating the current traffic modem status. (If the Node Control
Modem reports a bad status, the MIDAS Controller terminates the
sequence.)
4. The Node Control Modems at the receiving traffic nodes configure the
traffic modem and enable the receive. They also respond with a status
message indicating the current traffic modem status.
5. The data circuit is established when one of the receiving traffic modem
locks.
6. The MIDAS operator is informed of the progress of the circuit setup
through the operator workstation.