Use of internal serial port of router TPLINK

Greetings, I have a query, I got the USB / Serial DB9 cable, and I know that all (or most) of the TPLink router have an access via internal serial port (without most pins) my doubts go there:

Can the USB / DB9 cable be connected directly to these pins (soldering pins and placing simple cables)?
Is another special cable needed to remove the serial port?
If you can connect directly What is the pin mapping in DB2 with the four pins of the router?

Saludos, tengo una consulta, he conseguido el cable USB/Serial DB9, y se que todos (o la mayoria) de router TPLink tienen un acceso via puerto serie interno (sin pines la mayoria) mis dudas van por ahi:

¿Se puede conectar directo el cable USB/DB9 a esos pines (soldando pines y colocando cables simples)?
¿Se necesita de otro cable especial para sacar el puerto serie?
Si se puede conectar directo ¿Cual es la correspondencia de pines en DB2 con los cuatro pines del router?cable-serie-usb-rs232-uart-ttl-serial-db9-9-pin

No, you can't use that cable at all. Routers require 3.3 volts based UARTs, while your cable can go up to +/- 25 volts, which would destroy the router if you'd attach it.

You want something like this: (highly recommended, works great)|0

Beware of fake FTDI and Prolific serial converters

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Nice introduction to UART serial !!! Don’t forget to cross the pin !!! (As I did) :crazy_face:

I have ordered this product, I hope it is the one I need

He pedido este producto, espero sea el que necesito

It may be fine but it's known to be counterfeit.
HXA is also as noted above not supported by Windows 8+ (you need HXD of the HX series)
You should be fine I guess if you run Linux or BSD and/or if you get a HXD version.

Prolific has decided to no longer support even genuine PL2303HX chips with their Windows driver. To me that's a clear message not to buy their stuff.

HXD still works fine, I'm also very happy with my PL2303TA adapter.

The Owen Duffy page agrees with me:

... the safe option is to avoid Prolific chips altogether

FTDI has also been the victim of counterfeiting but they aren't doing shenanigans that cut off legitimate users like Prolific did. For now the HXD is OK, but for how long?
It's a simple USB to async bridge chip. That means two things:

  • It's not going to be complicated for someone to make knockoff chips that are logically identical to yours.
  • It should not be difficult to support it until basically the end of time.

No hardware is going to be supported until inifinity and you have other options which I linked to above if you want ot use something else than Prolific hardware.

i try rs232 in my router tp-link w8970 with 3 pins only
not work get this
and then used USB TTL work and install Firmware without any problem
the rs232 not work only usb TTL

but i think arduino is may be work !
arduino or usb ttl
arduino make everything !
but recommended used USB TTL

Ways to Use Arduino as USB to TTL Converter © GPL3+

RS232 will almost certainly fry any all-in-one router's serial port. "RS-232 drivers and receivers must be able to withstand indefinite short circuit to ground or to any voltage level up to ±25 volts." TTL logic levels (5V) have the potential to do so as well as most run 3.3 V logic levels, if not less.

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