(2) Traffic flow. The network must be analyzed to ensure that the network design
can handle the flow of communications. The direction and volume of traffic, the types of traffic
(voice and data); and the analog/digital mix of instruments must be considered.
(3) Interconnection. This involves deciding how to connect the area nodes via cable,
LOS radio, troposcatter, SATCOM, etc.
(4) Extension systems. After the node locations and the backbone network have been
developed, extension systems to subscribers must be planned. This includes types and numbers
of equipment to support all validated requirements.
(5) Providing service. After the type and quantity of service required has been
determined, details on how the service will be provided must be worked out with the user. This
includes the location of communications equipment and responsibilities for installation and set
up of terminal equipment (telephones, facsimile, teletypewriter, etc.).
(6) System connectivity. The next step is to complete the systems diagram by
ensuring that all nodes are interconnected, to include connectivity from higher to lower and to
(7) Allocating frequencies. The final step is to allocate operating frequencies. This
d. Circuit switch systems engineering deals with the technical aspects of designing and
establishing an effective network that will handle the projected traffic flow in an efficient and
effective manner. The goal is to provide all subscribers with a specified grade of service. After
the network has been designed and the trunk sizes determined to satisfy the grade of service, the
following steps should be taken as part of this process:
(1) The circuit switch diagram should be developed to provide the network planner
with a graphic representation of the network, to include primary zone switch location, circuit
switch site identification, circuit switch type, trunk group number, and type.
(2) Switch operations. An automatic switch must be programmed before it can
perform its functions. This consists of a data base of a series of data lists or tables. The tables
give the switch processor the information it needs to route and switch calls. Before a switch can
be programmed, the network planner must make decisions on certain switch operations.
(a) The AN/TTC-39 circuit switch can operate at either a 16 or 32-kilobit digital
channel rate. The 16-kilobit rate is only used when the entire network is digital. The 32-kilobit
rate is used when analog-to-digital or digital-to-analog conversion is required.