Control Data Corporation 6000 Series Reference Manual page 5

1. INTRODUCTION
The CONTROL DATA* 6675 Data Set Controller interfaces Control Data 6000 Series
Computers with leased telephone transmission lines. This enables data transfer
between a central computer complex and a remote computer system.
The Control Data 6675 consists of a Data Channel Adaptor (DCA), a multiplexer, and
up to four data set controllers (DSC's).
The 6675 cabinet also provides mounting for
DATA PHONE data sets**· Each installation determines how many DSC's and data
sets are used as well as the type of data set (201-B, 301-B, X303A10) used. Com-
munication over leased line requires two AT&T data sets; one data set terminates
each end of the transmission line.
Figure 1-1showsa6675 equipped with four DSC's. The multiplexer assigns indi-
vidual DSC' s to transmit or receive. Each DSC converts 12-bit parallel words from
the computer (via the DCA) to serial bits for the data set. The data set transmits
serial data received from the DSC over a leased transmission line. The DSC at the
receiving end of the line converts this serial data into 12-bit parallel words for
computer input.
Each DSC includes a cyclic code generator and error detection circuit that enables
detection of error bursts of 12 bi ts or less. An error burst is any pattern of errors
whose length is the number of bits between the first and last errors of a transmission.
*Registered trademark of Control Data Corporation.
**Registered trademark of American Telephone and Telegraph Company and Bell
System.
Rev. A 1-1