USB 3.0 versus Ethernet LAN interface?

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Max
Posts: 858
Joined: Thu Aug 13, 2020 9:47 am

USB 3.0 versus Ethernet LAN interface?

#1

Unread post by Max »

Can someone please explain to me the pros and cons of these two interfaces for an SDR?

Reason for question. I have an HL2 (Hermes Lite 2) with LAN interface, and the RX888 (I don't yet own) is supplied with USB 3.0.

I would have thought (from my point of relative ignorance) that high speed LAN would always be preferable over a USB interface because of the greater ease of remote operation?

Any ideas why designer of RX88 and others seem to favour USB interfaces? Or why not provide both?

Thanks for looking

Max

jdow
Posts: 799
Joined: Mon Aug 10, 2020 8:17 pm

Re: USB 3.0 versus Ethernet LAN interface?

#2

Unread post by jdow »

Note that USB3.0 has higher basic bit rates available than does gigabit Ethernet.
{^_^}

Max
Posts: 858
Joined: Thu Aug 13, 2020 9:47 am

Re: USB 3.0 versus Ethernet LAN interface?

#3

Unread post by Max »

Thank Joanne for reply. Coincidentally there was a debate about this on the "NextGen SDRs" IO Group that discussed the same issue shortly after I posted the question on here:

https://groups.io/g/NextGenSDRs/message/16

Stated there that max throughput on USB 3.0 is 5 Gb/s so as you say, considerably more than Gigabit ethernet. I guess the limitation imposed here is length of cable to the remote unit? Not a major issue for me as I am not operating remotely anyway.

73

Max

bagmouse7
Posts: 43
Joined: Sat Aug 22, 2020 4:24 pm

Re: USB 3.0 versus Ethernet LAN interface?

#4

Unread post by bagmouse7 »

I think there are 2 other big issues.
I think a USB interface is much easier to support on the SDR device. If you put an Ethernet interface on the device you need to build a full IP stack to support it and that implies a host CPU on the SDR and code on the device to get the data out of the SDR. The USB interface is way easier to support on the host side and the CPU can be much simpler.
Also, you need a more powerful device CPU to pull the data off RF chipset, convert it to IP and sent it out the Ethernet interface.

I would prefer Ethernet over USB for many reasons, but for really wide bandwidth SDRs, it looks like USB3 is the best/cheapest way to go right now.

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