Section 060-INDP-111 System Description 2-25
BMC II BISYNC Operation, Administration, and Maintenance Guide BMCB001 and up
Tape Emulation Circuit/Data Stream Interface PCA
The BMC application eliminates the Magnetic Tape Drives (MTDs) used with
theSwitchingSystemstocollectAutomaticMessageAccounting(AMA)data.
The four TEC/DSI PCAs (slots 12 and 13 in the A and B chassis) in the BMC
replace the MTDs.
The TEC/DSI packs are smart PCAs, each with its own Z80 microprocessors,
EPROM-resident software programs, and RAM. Since MTD emulation re-
quires the BMC to maintain redundant communication with the Switching Sys-
tem, the TEC/DSI PCAs are active devices. The TEC/DSI software program
receives and processes commands the Switching System normally sends to the
MTD. This software also responds with the status and strobe signals the MTDs
normally return to the Switching System. Furthermore, these packs handle the
call record data from the Switching System.
The data path from the Switching System to BMC is through TEC/DSI cable
adapter assemblies, contained in interface boxes installed near the BMC. The
TEC/DSI cable adapter assemblies duplicate the connections for the cables
that normally interface the Switching System to the MTDs. The Switching
System MTD ports plug into an interface box that provides connectors for the
control and status, read, and write leads from the Switching System. System
signals are passed through the interface boxes to J connectors on the BMC.
From the - connectors, the signals are routed internally to the TEC/DSI PCAs.
The TEC/DSI PCAs serve the primary function of receiving call record AMA
data blocks from the Switching System, to process those records (where
required), and to make this data available for transfer to the correct buffer in
the main CPU.
Output signals from the Switching System MTD ports come through the
interface box ribbon cables and adapters and arrive at the TEC/DSI PCA
input ports.
Bus Terminator PCA
The Bus Terminator PCA, in slot 14 of the A and B chassis, contains a power
regulator. This regulator provides circuitry to terminate the end of the bus
which prevents ringing (oscillation) of signals on the bus.
SCSI Crossover PCA
The SCSI Crossover PCAs are located at positions A15 and B15 on the inner
portion of the hinged card panel at the rear of the A and B chassis. They are
connected between both SCSI Interface PCAs in the BMC (A side and B
side) and both SCSI Disk Drive assemblies (Disk 1, disk A at A21; Disk 2,
disk B at B21).
The system interface ports of the SCSI Crossover PCAs (40-pin connectors J1
& J2) consist of 8 data lines with parity and 12 control lines. One port is
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