Specifications

The numbers a user needs. Every value comes from the design files of the unit.

Power

The table gives the power figures.

Item	Value
Charger	A USB-C charger rated 5 V at 3 A (15 W), with a USB-C to USB-C cable. Plug it into the 5V 3A port.
Host port supply	The PC port also takes 5 V from the computer. A computer port is never enough for high power.
Which source feeds the unit	The charger, when present. The host port then carries data only.
Input voltage	5 V only. Never feed 9 V, 12 V or 20 V. The unit has no power-delivery contract.
Cable rail	3.3 V, up to 2 A. The power switch (MOD PWR in the software) switches the rail.
Stand-alone draw	About 0.6 A at 5 V with a cable in low power.
Software budget	6.0 W. The software releases a cable to high power only when the cable declares 6.0 W or less.

Power classes

A QSFP-DD cable declares a power class. The software reads it before it releases the cable. The table shows what the tester allows.

Class	Declared maximum	The tester
1	1.5 W	Allowed. Hood off.
2	3.5 W	Allowed. Hood off and a fan over the heat sink.
3	7 W	Allowed only when the cable declares 6.0 W or less. Hood off and a fan over the heat sink.
4 to 7	8 W to 14 W	Refused. The verdict reads OVER-JIG-BUDGET.
8	above 14 W	Refused.

The software watches the cable temperature every second during a powered step. It warns at the warning level of the cable. It pulls the cable back to low power at the throttle point. That point is 5 °C below the cable's alarm level, or 70 °C. The lower value wins. The verdict then reads THERMAL.

Cables supported

The table lists what the tester reads and tests.

Item	Value
Form factor	QSFP-DD.
Management	CMIS over the two-wire bus. We read cables with revisions 4.0 and 5.x.
Active electrical cable (AEC)	Yes. Both ends go into two units for the full test.
Optical transceiver	Yes, one per unit. For a two-end test, join two transceivers with a fibre trunk.
Pattern test	Runs inside the cable, when the cable offers it. The tester has no data lanes of its own.
What the tester does not do	No traffic from a host. No bit-error test from the host side.

Host

The table lists what the host computer needs.

Item	Value
Connection	One USB 2.0 port per unit. A pair needs two ports.
Operating system	Tested on Linux and macOS. Not tested on Windows.
Linux	aectest setup-linux installs the device rule.
macOS	Install libusb with Homebrew before the first run.
Python	3.11 or newer.
Software	The aectest package. It installs its own driver library.

Environment

The table gives the limits of the room and the box.

Item	Value
Room temperature	We checked the thermal design at 25 °C and 35 °C. No wider range is specified.
Case material	PLA. It softens at about 55 °C. Keep the unit under 50 °C.
Cooling	Hood off for every powered test. A class 2 or 3 cable needs a desk fan or a USB fan over the fins. You must feel the air at the fins.
Heat sink temperature	Up to 70 °C during a powered test.

Dimensions and mass

The table gives the size and the mass of one unit.

Item	Value
Length	147.1 mm, hood on.
Width	47.5 mm.
Height	32.6 mm over the hood, 23.6 mm over the lid.
Circuit board	42 mm by 136 mm.
Mass	We did not weigh the unit. The printed parts are about 80 g by the slicer. The board with its cage is about 54 g by calculation.