Question

Hi,

I can't drive the output on pin 4 and pin 3, I use both the web application as well as the command line.

ubus call ioman.gpio.dio0 update '{"value":"1"}'

[email protected]:~# ubus call ioman.gpio.dio0 status

{

        "value": "1",

        "direction": "out",

        "bi_dir": true,

        "invert_input": false

}

but on the output I have no Volt (from negative and the pin)

I follow this page (TRB142 Input/Output - Teltonika Networks Wiki (teltonika-networks.com)

I don't understand where I'm wrong

INFO:

Firmware version TRB1_R_00.07.01.4

Firmware build date 2022-02-25 08:21:08

Modem firmware version EC21EUGAR06A01M4G

Kernel version 3.18.20-msm

Comments

I understand how it works.

as long as a load is not put between the positive and the output pin, I cannot measure a voltage difference between the pin and the ground.

this beacuse the system is an open collector.

---

Hello,

You are indeed correct. In order for the output device that you connect to the output to work, you must attach the output device to a positive voltage source.

Best regards,

Žygimantas

Answer 1

As long as a load is not put between the positive and the output pin, a voltage difference between the pin and the ground cannot be measured.

That is because the TRB142 has an open collector output.