The 709/7090 series use Data Synchronizer Channels for high speed input/output, such as tape and disk. The basic 7-bit DSCs, e.g., 7607, execute their own simple programs from the computer memory that controls the transfer of data between memory and the I/O devices; the more advanced 9-bit 7909 supports more sophisticated channel programs. Because the unit record equipment on the 709x was so slow, Punched card I/O and high-speed printing were often performed by transferring magnetic tapes to and from an off-line IBM 1401. Later, the data channels were used to connect a 7090 to a 7040 or a 7094 to a 7044 to form the IBM 7094/7044 Direct Coupled System (DCS). In that configuration, the 7044, which could use faster 1400 series peripherals, primarily handled I/O.