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Hard limit on VVX expansion BLF?

Occasional Visitor

Hard limit on VVX expansion BLF?



We have a VVX 411 with the color expansion module running UC

Connecting to an Asterisk/FreePBX server, working great.

We would like to use all available Line Keys on the system: 16 on the phone, 28 on the expansion unit = 44 keys.

Of the 12 keys on the phone we want 5 Line keys, 11 BLF.

We want all 28 keys on the expansion to be BLF. Total desired BLF = 39.


I followed the directions to create a mac-features.cfg file and the Line and BLF keys on the phone are good.

However, the number of BLFs on the expansion is maxing out at 22 (34-12=22). I define more BLF keys but they do not appear and there are 6 available slots on the expansion module.


This appears to be related to the message in the phone web interface:

Admin / Utilities / Link Key Configuration:

Active Line and Speed Dial Keys
Max = 34

We are not using the web interface for configuration but .cfg files.


I have seen somewhere in the docs there is a limit of 50 BLF keys but we are trying to define less than 50.


Can you explain the 34 limit?

Is this a hard limit on the expansion module or is there some way we can address all the keys?

It seems strange to sell a 28 key module but you cannot use all the keys.





Message 1 of 2
Polycom Employee & Community Manager

Re: Hard limit on VVX expansion BLF?

Hello @tesno2,

welcome to the Polycom Community.

The UC Software 5.7.0 Admin Guide lists the 34 line limit on page 306 in the section "Maximum Number of Registrations"


There is also a difference between the attendant.uri method and the attendant.resourceList.x.address.


The VoIP FAQ lists a few restrictions:


May 12, 2016 Question:Are there any limitations on Hunt Group's or BLF / Busy Lamp Field?

Resolution: Please check => here <= 


We are selling the expansion modules as they can be used as speed dials etc.


Please provide a backup of your configuration so someone can check if you made any mistakes.


Utilities > Phone Backup & Restore > Phone Backup > Phone Backup

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.


Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
Message 2 of 2