Aeroflex / Tektronix / CDS 53A-431 Quad UART RS-232/RS-422 Module

The Aeroflex / Tektronix / CDS 53A-431 is a quad-channel UART module providing independent RS-232 and RS-422 serial communication interfaces. Each of the four channels operates asynchronously with programmable baud rates, word lengths, stop bits, and parity control, supported by configurable transmit and receive buffers up to 4 KBytes per channel. The module integrates into CDSbus systems with full ASCII character programming, hardware flow control (RTS/CTS), and XON/XOFF protocol support.

Built-in diagnostics via LED indicators and per-channel loopback self-test capability ensure reliable operation across industrial and laboratory environments.

Technical Specifications

• Channels: Four independent asynchronous UART


• Interface Standards: EIA RS-232C (1969), EIA RS-422A (1978)


• Baud Rates (programmable per channel): 10, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200 baud; rates above 19200 require Option 03 with external clock


• Word Length (programmable per channel): 5, 6, 7, or 8 bits


• Stop Bits (programmable per channel): 1, 1.5, or 2 bits


• Parity: Odd, Even, or None (programmable per channel)


• Data Buffers: Transmit and Receive 0–4 KBytes per channel (1 KByte increments); 32 KBytes total on-card memory


• Flow Control: RTS/CTS, XON/XOFF


• Interrupts (programmable): Specific character, buffer size, buffer overflow, link error, XON/XOFF


• Logic Levels: Inverted or Non-inverted (switch-selectable)


• RS-422 Signals: Transmit 2 V to 5 V differential (100 Ω load); Receive 200 mV to 30 V differential


• RS-232 Signals: Transmit ±9 V to ±14 V (3000 Ω load); Receive +3 V to +30 V (space), -30 V to 0 V (mark)


• Operating Temperature: -10°C to +65°C


• Storage Temperature: -40°C to +85°C


• Humidity: <95% RH non-condensing (-10°C to +30°C); <75% RH non-condensing (+31°C to +40°C); <45% RH non-condensing (+41°C to +55°C)

Key Features

• Per-channel baud rate, word length, stop bit, and parity selection


• Programmable transmit/receive buffer allocation


• Error detection via parity and receive error flags


• Channel loopback self-test under program control


• LED diagnostics for RS-232/RS-422 signal status (TXD, RXD, CTS, DCD, DTR, RTS) and link programming errors

Typical Applications Multi-port serial interfaces for test systems, data acquisition, industrial control, and laboratory instrumentation requiring simultaneous independent RS-232 or RS-422 communication.

Compatibility & Integration Designed for CDSbus systems. Recommended cable: 53A-780. Cooling provided by 53/63 Card Cage fan.