Safety

Read this page before the first test. The rules protect the cable, the unit and your fingers.

Power-up order

Leave the switches as shipped. The power switch (MOD PWR in the software) is at ON. MODE is at AUTO. The three slides are at O.
Take the hood off.
Plug the charger into the 5V 3A port (PWR ONLY in the software). The 5V IN light comes on.
Plug the host cable into the PC port. The USB light comes on.
Start the software. The PC light comes on when the software opens the unit.
Insert the cable. The PRES light comes on.

Power down in the reverse order. Let the software return the cable to low power first. The LPMD light comes on. Then pull the cable, the host cable and the charger.

The charger rule

High power needs a charger rated 5 V at 3 A on the 5V 3A port. A computer port cannot supply it. The unit cannot sense which supply is present. The software asks you to confirm the charger before it releases a cable to high power. Confirm only when the 5V IN light is on.

Plug the charger in before the host cable. A charger plugged in after the host cable dips the supply for a moment.

Never unplug the charger while a cable is in high power. The load moves to the computer port. The computer port cannot carry it. The POWER light flickers and the cable loses power.

Hot parts

The heat sink and the cable plug reach the temperature of the cable. That can be 70 °C. With the hood off the fins stand open.

Do not touch the heat sink during a powered test or right after it.
Hold the plug by its pull tab when you remove a cable.
Let a cable cool before you pull it after a THERMAL stop.
Use a fan with a finger guard. Keep cable tails out of the fan. A class 2 or higher cable needs the fan.

Static electricity

Handle the closed unit by its box.
Wear a wrist strap at the bench when you handle cables.
The cable plug makes ground first when you insert it. You need not switch the power switch off to insert a cable.
Keep the hood on and the unit in an anti-static bag for storage.

What never to do

Never plug the host cable in before the charger.
Never pull the cable, switch the power switch off, or unplug the charger while the LPMD light is dark.
Never run a powered test with the hood on. The closed box cannot cool a powered cable.
Never feed the unit from a 9 V, 12 V or 20 V supply. Both ports are 5 V only.
Never use a computer port as the supply for high power.
Never move a slide switch while the software runs a test.
Never move LPMD off H in stand-alone mode. Without the software nothing watches the cable temperature.
Never open the box, and never touch the board, its pins or its straps.
Never lift the unit by the cable.
Never put anything but a QSFP-DD plug into the cable port.

What the software blocks for you

The table lists each check and what the software does.

Check	What happens
No charger confirmed	The software refuses to release a cable to high power.
Cable declares more than 6.0 W	The software refuses to release it. The verdict reads `OVER-JIG-BUDGET`.
Cable gets warm	A `WARN` line at the warning level of the cable. The test continues.
Cable gets hot	The software pulls the cable back to low power and stops. The verdict reads `THERMAL`.
A switch is wrong	The pre-check names the switch. Fix it and press Retry.
A unit is missing	The verdict reads `JIG-UNIT-MISSING` before any step runs.
The jig profile records a cut strap	The software refuses the unit. Command line only. Send the unit back.
Cable end lost during a test	The test stops. The verdict reads `REMOVED-MID-TEST`.
Pattern test shorter than 60 s	The software treats it as a rehearsal, not a record.

The software always returns a cable to low power at the end of a run. If you must stop a run, use the Stop button or Ctrl-C. Then wait for the LPMD light.