TP-Link TL-PA4010

TP-Link · HomePlug AV powerline adapter, single 10/100 Ethernet port · TL-PA4010

Illustrative drawing in proportions from the vendor datasheet (approximate layout)

what it is

A powerline adapter plugged directly into a wall outlet: it carries Ethernet over the power wiring to a second adapter in the same electrical installation. One 10/100 Mb/s port on the bottom of the casing, three LEDs — PWR, PLC and ETH — and a Pair button. Casing 65 × 52 × 28.5 mm (manufacturer datasheet), versions with EU, UK and US plugs.

Inside runs a Qualcomm Atheros QCA7420 chip — that is how the firmware identifies itself in a reading from the device (MAC-QCA7420-…). The marketing designation changed between hardware versions: the manual for the first version refers to the AV500 class, later materials to AV600.

The 10/100 port is the limit of the entire link. The switch port the adapter is plugged into will show 100 Mb/s — this is not a symptom of a bad cable, it is simply all this adapter can do.

what we read from it

The adapter has no IP stack: no address, web page, SNMP or ping. The only path is HomePlug AV management frames (Ethertype 0x88E1), sent from any machine in the same layer 2 domain — on either side of the link. The open-source plc-utils tools query them without credentials.

PHY rate separately in each direction. No Ethernet port will show this number.
Roles in the powerline network: which adapter is the coordinator (CCO) and which is a station (STA), plus the TEI numbers.
The addresses of both adapters and the address of the device behind each of them (BDA). From the latter you can determine which switch and port each plug sits behind — without opening the rack.
Firmware version of each adapter and the network identifier (NID, SNID).
PHY block and frame counters since the last reset in the device.

link measurement

Five readings over about 20 minutes (September 5, 2026) gave transmit and receive PHY rates of: 72/58, 72/59, 73/59, 66/62 and 72/60 Mb/s. For a link sold as 600 Mb/s that is about 60–73 Mb/s PHY, and usable throughput is lower still.

The number fluctuates and is asymmetric. A single reading says little — only a series over time makes sense, set against what is happening in the electrical installation.

PHY rate is not throughput. It is the link capacity negotiated between the adapters. How much actually flows is shown only by the counters of the switch port at the adapter. Comparing the two distinguishes two cases: throughput close to the PHY rate is a saturated link; low throughput with a falling rate is a link that is degrading on its own.

measured pitfalls

Invisible to any IP-based scan. It does not answer ARP or ping, and the switch does not have it in its MAC table: in a complete set of 36 entries (September 5, 2026) there was no adapter address. The adapter is a transparent bridge and never transmits with its own source address.
LLDP and CDP do not see it. The switch shows the device on the other side of the link as if it were connected directly by cable.
Management requires no password. The same path that reads the state allows writing the powerline network key — a single frame breaks the link. Use write commands (plcset, plcID -w, plchost) only deliberately, and keep the network key (NMK) out of the documentation. The network identifier (NID) is visible to anyone in the segment.
plcstat -C resets the link counters — that is, it erases the only history the device has.
An empty query result does not prove the adapter is absent. Missing root privileges, a wrong interface and a different layer 2 domain look exactly the same.

the Pair button

Holding it for 1 second creates or joins a secure powerline network — the button is pressed on two adapters in turn. Holding it for 8 seconds removes the adapter from the existing network (quick installation guide, version 1). The PLC LED is lit when the adapter is in the network and blinks when the signal from the outlet is weak.

what we cannot read

Throughput — the adapter does not measure it; the switch port counters do.
Interference spectrum in the electrical installation — there is only the PHY rate.
Anything over SNMP — the device has neither an agent nor an address.

full parameter list

A full parameter list for this model is not here yet — the ones described above are those we have read and verified. A missing list does not mean the device exposes nothing more.