# Replacing USB dongle / using multiple dongles

**URL:** <https://forum.hardwario.com/t/replacing-usb-dongle-using-multiple-dongles/742>\
**Category:** TOWER\
**Created:** [March 20, 2023, 8:50am UTC](https://forum.hardwario.com/t/replacing-usb-dongle-using-multiple-dongles/742 "2023-03-20T08:50:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mixi](https://forum.hardwario.com/letter_avatar_proxy/v4/letter/m/dbc845/32.png) [@mixi](https://forum.hardwario.com/u/mixi)\
**Post date:** [March 20, 2023, 8:50am UTC](https://forum.hardwario.com/t/replacing-usb-dongle-using-multiple-dongles/742/1 "2023-03-20T08:50:48Z")

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Hi,  
I have trouble with unreliable communication with some tower devices, so I would like to replace my current dongle with EA version. My question is:

1. is it possible just replace the dongle and migrate connected devices without need to individually repair them with new dongle?
2. is it safe to use multiple dongles concurrently on different machines (I would just connect new EA dongle and pair only some devices to it)?

I assume migration is not possible as you use security chips on dongles and allowing migration would be security flaw.  
Regarding multiple dongles, I don’t see any problems, but I’d like to have this confirmed to prevent any suprises. 🙂

Thanks for info.  
Mixi

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**Author:** ![hub.martin](https://forum.hardwario.com/user_avatar/forum.hardwario.com/hub.martin/32/631_2.png) [@hub.martin](https://forum.hardwario.com/u/hub.martin)\
**Post date:** [March 20, 2023, 10:15am UTC](https://forum.hardwario.com/t/replacing-usb-dongle-using-multiple-dongles/742/2 "2023-03-20T10:15:44Z")

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Hi Mixi

the security chip is soldered, but it is not used yet.

Pairing information is saved in STM32L EEPROM. You can use `bcf eeprom` command to read and write it. So you can clone the pairing information from one dongle to another one “EA”.

However, it is not possible (ok, it was, but not suggested 🙂 ) to pair a single node to a multiple dongles.

So you can clone paired nodes with that EEPROM and then remove them in a way that every node is paired only on a single dongle.

Then you can run two dongles, each with its own `bcg` service and connect them to a single mqtt broker.  
In `bcg` tool there is parameter to name the dongle differently, you cannot have both of them with a same name. Or you can change name in the bcg config file.

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<div class="post-metadata">

**Author:** ![mixi](https://forum.hardwario.com/letter_avatar_proxy/v4/letter/m/dbc845/32.png) [@mixi](https://forum.hardwario.com/u/mixi)\
**Post date:** [March 20, 2023, 1:31pm UTC](https://forum.hardwario.com/t/replacing-usb-dongle-using-multiple-dongles/742/3 "2023-03-20T13:31:18Z")

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Thanks much for the info, I’m glad I won’t be running all around and re-pairing devices 🙂

This got me thinking though, about implementing redundancy by having active/standby pairings and some mechanism for detecting outages and controlling which dongle communicates with particular devices… but no, this is just hobby project and not work, so I must be strong and avoid having such ideas 😃