EN-DC / Carrier Aggregation documentation missing - use !RFCOMBOS instead

For unknown reasons, Sierra still refuses to provide any detailed information about supported Carrier Aggregation and EN-DC band combinations.

Fortunately, the module provides this information itself, via the undocumented “AT!RFCOMBOS” command:

Total combos: 3571
  • Each line describes an allowed combination.
  • Discontigous Bands are separated by ‘+’
  • Each Band number is followed by the LTE Bandwidth Class, [A-E]
  • Next is the number of MIMO layers, if the Bandwidth class allows multiple component carriers (e.g. 4 for ‘E’) there is one number per CC
  • If a Band also supports an Uplink, this is separated by ‘;’ followed by bandwidth class and MIMO layers

I.e. for the “B3A[4];A[1]+B1A[4]+B3A[4]+B7A[4]+B28A[2]” entry above:

  • 5 carriers total
  • two discontigous component carriers in B3, i.e. there may be a frequency gap between the two
  • the first four Bands each support 4 layer MIMO, B28 only 2 layer MIMO
  • only one uplink with one MIMO layer


  • 3 Bands
  • 2 uplinks, B3 and B28


  • Four component carriers in B48, i.e. up to 4*20MHz bandwidth
  • EN-DC with 5G-NR in Band 66, with four MIMO layers. 5G-NR Bandwidth class A. (Note: Bandwidth classes for LTE and 5G-NR are different).
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Hi @stefanbruens

Our 5G customers would have received this information via their support contacts. Do reach out to your support team with your questions and we will be happy to help you.

Your feedback is noted and we will act on it soon :slight_smile:

We have been asking for months, both our distributor and the assigned FAE.

The document is not publicly available yet. Please ask your distributor to open a support case to us and we can certainly provide the information that you are looking for. If you’d opened a ticket already, please provide that number and I can follow up.

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