Altinex TE460-137 Teardown

It is surprisingly hard to find a device that can dump details about the various protocols and negotiated standards for a HDMI connection. For how ubiquitous HDMI is, you’d think that there would be a lot of devices that can do this. There are LOADS of devices that can snoop USB and Ethernet, but HDMI is a bit of a different beast, apparently.

After a bit of searching, I found the Altinex TE460-137 could do exactly what I wanted.

(/enhanced-homeassistantswitchplate/) project.

Like the HDMI CEC dongle this device is a bit specialized and so there’s not a lot of readily available information about it online. I was curious about what’s inside and how it works, so I decided to take a look.

Magnuson-Moss Warranty Act

Notice that pierced Warranty void if removed sticker over the bottom right screw? Yeah, that’s illegal. Naturally, companies don’t want you to know that the sticker is unenforceable.

Consider this a small PSA: if you see a sticker like this, you can safely ignore it. The company cannot void your warranty for removing it but they absolutely can make your life difficult if you do. If you get pushback, direct them to the FTC’s official statement on the matter.

Anyways.

Quick peek Inside

After removing the four screws, the case splits open easily enough. The construction is a bit more elaborate than expected; there’s a main PCB, a control PCB, and a battery interface PCB.

I was in a hurry so the photos are “as-is” and not my best work. I’ve noted down the markings on the chips and other components for future reference.

If the battery ever does leak, the entire PCB assembly can be removed and replaced. It also shouldn’t be that difficult to just modify the battery interface PCB to use a different battery. The thermistor is a nice touch!

Taking a quick look at the control PCB, we can see a few big ICs… The populated JTAG header is an interesting find.

There’s not much on the rear of the control PCB:

Nor is there much on the side of the PCB just behind the OLED screen / front panel. Oddly enough, each button gets two sets of contacts…

And there’s nothing interesting on the ‘internal’ side of the front panel:

Some Technical Details

If you catch the device early enough in boot, you can see the panasonic HDMI switch chip enumerating in it’s default state. Don’t ask me where the 2% overscan comes from…

Chips and other markings

Control PCB

• The main application processor is the NXP LPC1830FET100.
• It seems like all audio is handled by the Analog Devices ADAU1701.

Oddly enough there are two flash chips here. Presumably firmware storage for the NXP and Analog Devices chips.

• Winbond 25Q32JV
• Microchip 24LC128I

I didn’t bother dumping either, but Altinex does make an older version of the firmware available.

Main PCB

The big QFP144 chip on the main PCB is a Panasonic MN864788. I can’t find a data sheet, but one supplier has labeled it a “HDMI 2.0 Receiver/Switch”. Given the proximity to the two HDMI ports … this makes sense.

dmesg

For thoroughness, here’s how the device enumerates over USB when plugged in when configured in RS-232 mode:

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usb 5-4.1.2.2: new full-speed USB device number 91 using xhci_hcd
usb 5-4.1.2.2: New USB device found, idVendor=04e2, idProduct=1411, bcdDevice= 0.01
usb 5-4.1.2.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 5-4.1.2.2: Product: XR21B1411
usb 5-4.1.2.2: Manufacturer: Exar Corp.
usb 5-4.1.2.2: SerialNumber: Q9065270561
usbcore: registered new interface driver xr_serial
usbserial: USB Serial support registered for xr_serial
xr_serial 5-4.1.2.2:1.0: xr_serial converter detected
usb 5-4.1.2.2: xr_serial converter now attached to ttyUSB0

And when in FW update mode:

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usb 5-4.1.2.2: new high-speed USB device number 92 using xhci_hcd
usb 5-4.1.2.2: config 1 interface 0 altsetting 0 bulk endpoint 0x83 has invalid maxpacket 64
usb 5-4.1.2.2: config 1 interface 0 altsetting 0 bulk endpoint 0x2 has invalid maxpacket 64
usb 5-4.1.2.2: New USB device found, idVendor=1fc9, idProduct=8001, bcdDevice= 1.00
usb 5-4.1.2.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 5-4.1.2.2: Product: USB Mass Storage            
usb 5-4.1.2.2: Manufacturer: USB
usb-storage 5-4.1.2.2:1.0: USB Mass Storage device detected
scsi host4: usb-storage 5-4.1.2.2:1.0
scsi 4:0:0:0: Direct-Access     NXP      Dataflash Disk   0.00 PQ: 0 ANSI: 0
sd 4:0:0:0: [sda] 3968 512-byte logical blocks: (2.03 MB/1.94 MiB)
sd 4:0:0:0: [sda] Write Protect is off
sd 4:0:0:0: [sda] Mode Sense: 00 00 00 00
sd 4:0:0:0: [sda] Asking for cache data failed
sd 4:0:0:0: [sda] Assuming drive cache: write through
usb 5-4.1.2.2: reset high-speed USB device number 92 using xhci_hcd
usb 5-4.1.2.2: device descriptor read/64, error -110

Firmware