Early hardware · Open source (MIT)

Network Goblin ND-2

A Linux-powered handheld network multitool with real cable diagnostics. A custom carrier board for the Raspberry Pi Compute Module 5, with a dedicated cable-test port, a second gigabit port, a touchscreen and a battery.

A normal Linux underneath, so tcpdump, Wireshark, iperf3, nmap and friends just work.

Follow on GitHub The first board

ND-2 TDR proof dongle PCB layout, top copper: USB 3 at one end, RJ45 jack at the other

Status: early hardware. The first board, the TDR proof dongle, is at the fab. The full ND-2 carrier is still at the spec stage. Nothing has been tested on real hardware yet.

The plan

What ND-2 will do

Test port with TDR

Opens, shorts and distance-to-fault on each of the four pairs, from a gigabit PHY.

Second gigabit port

For uplink, packet capture and inline tapping.

Real Linux

Wireshark, iperf3 throughput, nmap and the rest of the toolbox, on a handheld.

Handheld

Touchscreen, battery power, 2× USB-A and HDMI out.

Open everything

KiCad hardware and software under MIT. Build it, fork it, sell it.

ND-1's big sibling

ND-1 stays the cheap instant-on pocket tester; ND-2 is the Linux multitool.

Rev A

The TDR proof dongle

A 70 × 30 mm USB 3 to gigabit Ethernet dongle that's just the ND-2 test port. It proves that ethtool --cable-test works on this chip combo before building the full carrier. And if it works, plug it into any Pi 5 or Linux laptop and you have a TDR cable tester.

TDR dongle PCB layout, top copper — Top copper.

TDR dongle PCB layout, bottom copper — Bottom copper.

USB 3 to MAC	Microchip LAN7801 (`lan78xx`, mainline Linux)
Gigabit PHY	Marvell 88E1512, with Virtual Cable Tester / TDR
Jack	HanRun HR911130C magjack with LEDs
Board	4-layer, 1.6 mm, all SMD on top, assembled by JLCPCB

Quick try (once you have one)

lsusb | grep 0424:7801
ip link
sudo ethtool --cable-test eth1

Unplug the far end of the cable first: TDR results are unreliable with an active link partner.

Roadmap

Order of play

Stage 1: bring up the Rev A TDR dongle and prove ethtool --cable-test against real cables (in progress)
Stage 2: Rev B dongle as a product of its own: USB-C, cheaper assembly, a case, packaged software
Stage 3: the ND-2 carrier: CM5, touchscreen, USB-C power delivery, 2S battery with fuel gauge
Stage 4: software: cable test, link/speed test, capture, inline tap, iperf3, scan, report export

Details in docs/roadmap.md and the draft spec.

Help wanted

Contribute

Hardware review, bring-up results and software are all welcome. Bring-up reports on real boards are especially useful right now.

Not certified: ND-2 isn't FCC/CE certified and isn't a TIA/ISO cable certifier. It tells you whether a cable is healthy enough, not whether it passes a formal certification test.