4707 Jun65

The 4707 Teletype Transmitter is a parallel-to-serial converter designed as a double-length DEC System Module board. Its primary purpose is to transfer 8-bit parallel digital data from an external device to an outgoing serial asynchronous teletype line.

Key features and operations include:

• Conversion Process: It disassembles an 8-bit data character in a shift register, adding a Start bit (followed by the least significant data bit) and a Stop element.
• Configurable Stop Element: The Stop element duration is jumper-selectable, allowing for 1.0, 1.5, or 2.0 units of stop time.
• Flow Control: An "Enable" input allows an external device to load a character into the shift register. Once a character is transmitted, a "Flag" output is turned on, signaling readiness for the next character. A "Wait" input can prevent the Stop Element Counter from timing out, facilitating half-duplex operations.
• Clock Input: Requires a clock input at twice the desired baud or bit frequency, with a maximum of 25 KHz, supporting baud rates up to 12.5 KHz.
• Outputs: Provides two data output terminals with dual complementary outputs, an "Active" status, and the "Flag" output (which also has an indicator lamp and control switch).
• Versatility: While designed for teletype, it can interface with other serial devices like computer systems or displays.
• Power Requirements: Operates on -15 volts (210 mA) and +10 volts (7 mA).

The module handles all necessary buffering, gating, and synchronization for the conversion process.