AC-30 Cassette Interface

SWTPC AC-30 Cassette Interface

Been looking for a practical way to input and dump programs to your computer? Well your search is over.

With our new AC-30 Cassette Interface you will be able to store and input program data to any computer system having RS-232 serial interfaces and a UART circuit having an accessible 16X clock frequency. Data format is the "Kansas City" standard which was selected for its tolerance of speed variations in the recording device. The AC-30 may be used with any cassette recorder of reasonable quality.

If both your computer and terminal have accessible 16X UART clocks and will operate at 300 baud-as do our 6800 computer and terminal system-the AC-30 may be used between the terminal's serial interface and the computer's control interface. This eliminates the need for a separate interface to drive the cassette unit. It also allows you to use the computer system's tape load and dump routines built into SWTBUG or similar ROM software.

Independent control circuits are provided for two audio cassette recorders (not included in the kit). One recorder's tape may be read while the second is recording a new updated tape; making it possible to generate new program tapes, data tapes and to create program object tapes while reading and assembling program source tapes. The operating mode for each recorder is selected by switches on the front panel and LED indicators show the mode that is selected at any particular time. Computer controller record, play and motor controlled commands may be used with this system if they are available from the terminal being used. This feature is available on our SWTPC terminals.

The AC-30 is housed in a 12 3/4" x 3" x 12 1/2" aluminum chassis. It is powered by a self contained 115/230 Volt AC 50-60 Hz power supply. Data is FSK format using 1200 hz and 2400 Hz at a 300 baud data rate. Recorder speed tolerance need be only +20%.

AC-30 Cassette Interface Kit was introduced in May 1976 and cost $79.50.

SWTPC AC-30 Cassette Interface ( case open)

Byte Magazine Article Dec. 1976

Kansas City Standard

AC-30 Assembly Instructions (113K PDF)

AC-30 Red and Blue Board Layout (248K JPG)

AC-30 Switching Schematic (382 JPG)

AC-30 Wring Diagram 1 (183 JPG)

AC-30 Wring Diagram 2 (191 JPG)

SWTPC 6800 / CT-1024 Interconnect Diagram (181K JPG)

AC-30 Diagnostic and Calibration Programs (23K PDF)

Program Source Code (2K TXT)

AC-30_Modification (65K PDF)

Sound File Sample (62K WAV)

Memory Test Program Sound File - MEMCON (165K ZIP)

Other I/O Devices
Michael Holley's SWTPC Collection Home Page
This page was last edited August 14, 2013