Agilent Technologies e4418b, e4419b manual A4 Comms Assembly

Theory of Operation

A4 Comms Assembly

A4 Comms Assembly

The comms assembly contains the circuitry required for remote control of the power meter. This assembly supports parallel and serial interfaces.

The GP-IB interface is supported by a protocol controller integrated circuit and two physical interface buffers. The system clock is divided by four to provide the GP-IB controller integrated circuit clock signal.

The RS232 and RS422 interface is supported by a single Universal Asynchronous Receiver/Transceiver (UART) integrated circuit and a programmable transceiver. The programmable transceiver can be configured for either RS232 or RS422. The remote interface is designated a DTE (Data Terminal Equipment).

The programmable baud rate generator in the UART is driven from the system clock (16.67 MHz) which allows baud rates in the range 50 to 115.2 K.

The whole assembly is connected to data, address, and control signals from the A2 processor assembly.

The comms assembly also provides a filtered path for the single/dual recorder output signal and the TTL input and output signals. It also provides ESD protection for the RS232.422, TTL I/O, and Recorder outputs.

4-8 Agilent E4418B/E4419B Service Guide