SN65HVD78: Does SN65HVD78DGK supports RS-422?

Choon Soo Kim

Prodigy 20 points

Part Number: SN65HVD78
Other Parts Discussed in Thread: THVD1452, SN65HVD76,

Tool/software:

Hi,

I have a few questions about SN65HVD78DGK.

1. Does SN65HVD78DGK transceiver supports RS-422?

The data sheet did not clearly state that it supports RS-422, although we could see the voltage and current content.

2. I know that SN65HVD78DGK transceiver supports half-duplex, does it support full-duplex?

Thanks.

6 months ago

+1 Clemens Ladisch 6 months ago

Guru 297570 points

1. For practical purposes, all RS-485 transceivers are compatible with RS-422.

2. Full duplex would require separate pins for the driver and the receiver. The SN65HVD76/77 or THVD1452/1451 would be full-duplex transceivers.

0 Choon Soo Kim 6 months ago in reply to Clemens Ladisch

Prodigy 20 points

Thank you!

+1 Ethan Sempsrott 6 months ago

TI__Expert 8397 points

Hi Choon,

Clemens is correct on this. SN65HVD78 does support RS-422 by nature of the standard. The datasheet doesn't explicitly state RS-422 compatibility, but it does mention that the device undergoes testing for RS-422 standards.

Full-duplex is not supported for SN65HVD78. As Clemens stated, SN65HVD76/77 supports full-duplex. For further clarification below, half duplex is illustrated on the top of the image, and full-duplex is on the bottom:

Please let us know of any other questions you might have.

Best,

Ethan

0 Choon Soo Kim 6 months ago in reply to Ethan Sempsrott

Prodigy 20 points

Thanks Ethan!

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SN65HVD78: Does SN65HVD78DGK supports RS-422?