# TX Switch and cnPulse as Cambium Sync sources

**URL:** https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160
**Category:** cnMatrix
**Created:** [March 2, 2026, 6:44pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160 "2026-03-02T18:44:23Z")
**Posts on this page:** 8
**Page:** 1

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### Author: ![DigitalMan2020](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/d/c6cbf5/32.png) [@DigitalMan2020](https://community.cambiumnetworks.com/u/DigitalMan2020)
#### Post date: [March 2, 2026, 6:44pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/1 "2026-03-02T18:44:23Z")

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> [@ePMP TDD Sync Sources White-paper](https://community.cambiumnetworks.com/t/epmp-tdd-sync-sources-white-paper/108153):
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> Applicable versions: 5.11.0 and above Applicable platforms: All GPS equipped Cambium ePMP radios employ Time Division Duplex (TDD), dividing each frequency channel into discrete downlink and uplink slots. Without synchronization, each Access Point (AP) determines its transmit timing independently. In multi-AP environments, this results in self-interference: the transmit cycle of one AP overlaps with the receive cycle of a neighbouring AP, degrading uplink performance and preventing effective f…

Thanks Andrii, if one is using a Tx switch doesn’t the switch need a gps, ie cnPulse, device plugged into the cnpulse port, I dont believe the tx switches have an internal gps module do they?

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### Author: ![Eric\_Ozrelic](https://d10gw3vjmzyp8.cloudfront.net/user_avatar/community.cambiumnetworks.com/eric_ozrelic/32/16188_2.png) [@Eric\_Ozrelic](https://community.cambiumnetworks.com/u/Eric_Ozrelic)
#### Post date: [March 2, 2026, 9:06pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/2 "2026-03-02T21:06:33Z")

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> [@DigitalMan2020](#):
>
> I dont believe the tx switches have an internal gps module do they?

They have an integrated GPS module, but it needs an external GPS antenna for it to work. You can also use cnPulse as a secondary source of GPS sync.

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### Author: ![DigitalMan2020](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/d/c6cbf5/32.png) [@DigitalMan2020](https://community.cambiumnetworks.com/u/DigitalMan2020)
#### Post date: [March 2, 2026, 9:55pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/3 "2026-03-02T21:55:38Z")

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Thanks Eric, We are using the cnPulse with a gps sync device. Question for you, I also have an external gps antenna, a gps puck, connected to the GPS module. If my cnpulse goes down should the module kick in? The reason I ask is that I did have the cnpulse go down and my connected devices did not recover gps and I could not tell if the module was working. Am I missing something?

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### Author: ![Eric\_Ozrelic](https://d10gw3vjmzyp8.cloudfront.net/user_avatar/community.cambiumnetworks.com/eric_ozrelic/32/16188_2.png) [@Eric\_Ozrelic](https://community.cambiumnetworks.com/u/Eric_Ozrelic)
#### Post date: [March 2, 2026, 10:04pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/4 "2026-03-02T22:04:45Z")

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Yes, if the switch has a GPS antenna connected with good signal, and if cnPulse is connected with good signal, the cnMatrix switch will use both for redundancy. This is automatic.

One thing to check, did you make sure that cnPulse admin status and power is enabled?

 ![image](https://d1okf4ta8xniw3.cloudfront.net/original/3X/2/e/2ee80ed07839788b386912922fa2072118464db7.png)

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<div class="post-metadata">

### Author: ![DigitalMan2020](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/d/c6cbf5/32.png) [@DigitalMan2020](https://community.cambiumnetworks.com/u/DigitalMan2020)
#### Post date: [March 3, 2026, 6:29pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/5 "2026-03-03T18:29:58Z")

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Hi Eric, thank you for your insight. I do have both enabled.

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### Author: ![DigitalMan2020](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/d/c6cbf5/32.png) [@DigitalMan2020](https://community.cambiumnetworks.com/u/DigitalMan2020)
#### Post date: [March 3, 2026, 7:39pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/6 "2026-03-03T19:39:32Z")

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@Eric_Ozrelic which one has priority, the gps antenna or the cnpulse?

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### Author: ![Eric\_Ozrelic](https://d10gw3vjmzyp8.cloudfront.net/user_avatar/community.cambiumnetworks.com/eric_ozrelic/32/16188_2.png) [@Eric\_Ozrelic](https://community.cambiumnetworks.com/u/Eric_Ozrelic)
#### Post date: [March 3, 2026, 7:47pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/7 "2026-03-03T19:47:52Z")

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The discussions I’ve had with the cnMatrix staff say that it uses both. There was no mention of priority.

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### Author: ![DigitalMan2020](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/d/c6cbf5/32.png) [@DigitalMan2020](https://community.cambiumnetworks.com/u/DigitalMan2020)
#### Post date: [March 3, 2026, 7:48pm UTC](https://community.cambiumnetworks.com/t/tx-switch-and-cnpulse-as-cambium-sync-sources/108160/8 "2026-03-03T19:48:54Z")

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Thank you very much, appreciate it.