Serial port hub adopting full/half duplex interchange mode

Abstract

The invention discloses a serial port hub adopting a full/half duplex interchange mode. The serial port hub comprises a plurality of serial port conversion units and a bus unit, wherein each serial port hub comprises a level conversion unit and a mode conversion unit; each level conversion unit is responsible for mutual conversion of an 232 level and a TTL (transistor-transistor logic) level, one end of each level conversion unit is accessed to R232 level signals R232_TX and R232_RX, and the other end is accessed to TTL level signals RX_IN and TX_OUT; each mode conversion unit is responsible for converting a TTL full-duplex signal into a TTL half-duplex signal and comprises two gate circuits G-A and G-B, on-off ends of the G-A and the G-B are connected with RX IN of an output end of the corresponding level conversion unit, an input end of the G-A is grounded, and an output end is connected with the bus unit; an input end of each G-B is connected with the bus unit, and an output end of each G-B is connected with the TX OUT of the output end of the corresponding level conversion unit. The serial port hub has simple circuits, very low cost and stable performance.

Description

technical field [0001] The invention relates to a data conversion device, in particular to a serial port hub in full and half duplex mode. Background technique [0002] At present, most commonly used serial port hubs, 485 hubs and other devices have many powerful functions, such as: baud rate self-adaptation, full-duplex / half-duplex conversion, etc. Most of these devices are composed of two parts: level conversion Circuits, circuit switching circuits, and some of the more advanced ones also have serial device address tracking; the above-mentioned level shifting circuits are generally divided into non-isolated and isolated, and are generally completed by some hardware level shifting chips. For example: the non-isolated ones include MAX232, MAX485, etc., the isolated ones include ADS3251, and the USB conversion chip is more commonly used in the FTDI series; and the above-mentioned circuit switching circuit is generally composed of a switcher and a data buffer, and they jointly...

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned equipment has only one uplink port; there is no connection between the downlink ports, and they cannot communicate with each other; there can only be one-to-one communication between the uplink port and the downlink port

Therefore, a "hierarchical" relationship wi

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