3Use the duplex printing option on your printer to use both sides of a sheet of paper.

3利用打印机的双面打印功能来使用纸的正反面。

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This paper presents a point-to-point radio half duplex asynchronous data communications protocol for microcomputers.

本文提出了一套适用于微机的半双工异步无线数据通信规程。

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Realization of a practical and integrated adaptive echo canceller applies in high speed full duplex Modem is proposed in this paper.

本文提出了一种实用、完整的自适应回波抵消器，可用于实现高速调制解调器的二线全双工传输。

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It supports duplex printing (automatically printing on both sides without having to manually re-insert the paper) and unlike some other printers, there is no separate attachment for duplex.

FORBES: Small and Affordable Brother Multifunction Device Prints 11 x 17-inch pages

For the PIXMA MG4220 Wireless and PIXMA MG3220 Wireless printers, Auto Duplex printing has been included to help reduce overall paper usage costs.

ENGADGET: Canon expands its PIXMA line with MG2220, MG3220 and MG4220 all-in-ones