Control Data Corporation 6000 Series Reference Manual page 7

The transmitting DSC generates a cyclic code with each data block transmitted. A
DSC may receive an interrupt word if
it
is not transmitting or receiving data. The
interrupt word sets a status bit in the DSC. The equipment contained in the 6675 is
described below:
The QSE 649 Data Channel Adaptor (DCA) is a high-speed interface between the 6675
and a 6000 Series Peripheral Processor data channel. Publication number CDC
38700100 describes the Data Channel Adaptor.
The multiplexer assigns each DSC to transmit or receive as directed by the computer
and permits up to four transmit or receive operations to occur simultaneously. The
exact number of high and low speed lines per multiplexer which can be serviced by
a Peripheral Processor depends on the amount of processing required for the input
data and on the manner in which this is handled by the operating system. The number
of lines can be determined after a careful analysis of system data flow.
The Data Set Controller (DSC) converts parallel data received from the computer to
serial data for the data set and vice versa. An American Telephone and Telegraph
(AT&T) Data Set connects to each DSC and transmission line to receive and transmit
serial data on the long distance communication facilities. The data sets provide
synchronous clock pulses to bit-time the DSC and to modulate or demodulate the
transmission line carrier. The data set consists of a signal controlled transceiver
with an internal oscillator that produces synchronous clock pulses. The data set
clocks out serial data from the DSC to phase modulate the carrier frequency during
transmission. The data set demodulates incoming line signals to recover control
signals and data.
*DATA TRANSMISSION LEASED LINE
SET (KILOBITS/ SECOND) OPERATION
201-A
2. 0
Yes
201-B 2.4
Yes
301-B
40.8
Yes
X303Al0 19.2
Yes
X303A20 50.0 Yes
X303A30 230.4
Yes
*When a Data Set is used with a 6675, the remote data set controller must be a
Control Data 3275, 63275, 8529, or 68529 to utilize the cyclic code error-detection
capability.
Rev.
A
1-3