BASIC BOARD MODULE (BBM)

SECTION 7 BASIC BOARD MODULE (BBM)
7.1 DESCRIPTION

The Basic Board Module (BBM) is the mother board of the following modules:

Dispatch Interface Module (DIM)

Intelligent Dispatch Module (IDM)

Dispatch Channel Module (DCM)

Channel Interface Module (CIM)

Telephone Interface Module (TIM)

System Network Module (SNM)

Conventional Channel Module (CCM)

Logging Encoder Module (LEM)

Voter Diagnostic Module (VDM)

Multi-Net Console Module (MCM)

Conventional Patch Module (CPM)

Wide Area Module (WAM)

These modules are made up of the BBM plus the appropriate software and personality cards as required.

The BBM uses four wire audio to connect to the external equipment. There is an additional connection for secondary data transmission.

7.1.1 MAIN AUDIO

The main external audio connection is via RXA±, P1, pins 31 and 32, and TXA±, P1, pins 63 and 64. These connections go to P33. This allows the personality cards to intercept the lines. When a 2-Wire connection is required on a module, it enters the card via the RXA± connection. The personality card then intercepts the signal on P33, pins 2 and 4. The receive and transmit buffers are connected to the personality card via P33 also. Refer to the Basic Board Module block diagram, Figure 7-1.

7.1.2 SECONDARY COMMUNICATION

There is a secondary communication connection to the BBM. This is used to pass data information to and from an external device, i.e. the Multi-Net Logic Module (MLM), another SNM, etc. These connections are the RXS±, P1, pins 27 and 28, and TXS±, P1, pins 59 and 60. There are two forms of communication on these lines, digital and audio frequency shift keyed data. The form of communication is determined by the switch setting of S3 and S4.

7.1.3 INTERNAL COMMUNICATION

There are several switch selections for the proper internal routing and use of the audio. This occurs via switch S1 and J27. There are several internal communication buses that are selected for operation of the microprocessor. These include both data and audio buses.

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