Envisalink4 and GSM monitoring issue

[Richel]

I have a Honeywell Vista 21 security panel and the Envasalink4. Integration with Homeseer via this plugin works. However, GSM monitoring is not working and I am being told by the security company that I can only have one or the other, not both. I really can't believe that this is correct. Can anyone corroborate this?
Thanks,
Elliott

[guppstir]

You must enable shadowing.
https://www.eyez-on.com/EZMAIN/evl4honeywell.php

IP/GSM/LRR Shadowing
The EnvisaLink 4 has the ability to work even if you already have an IP, GSM, or LRR module installed. This is done by a method called "shadowing". If you have such a module, and you have it enabled (*29 data field is set to 1), then click this check-box and hit modify. Failure to do this could result in both modules failing to operate correctly.

NOTE: If you DO NOT have an IP/GSM/LRR module installed and you check this checkbox, your EnvsaLink 3 will not function correctly.

NOTE: If you own a Vista 21iP, you MUST physically disable the onboard IP communicator for the EnvisaLink to function as communicator. You do this by removing the two-pin shunt on the jumper just below the onboard RJ-45 Jack on the Vista21IP panel. Please see the Vista 21IP Installation Manual for a full diagram.

[Guest]

Will shadowing work with a Vista21ip panel?