Polycom SoundStructure C16 Design Manual page 314

Cards Tool window indicates it is necessary to remove one telephony channel from the system based on
the number of telephony channels available.
Removing Telephony Channels
If you click Next and there are not enough telephony resources available, the following alert is displayed.
Telephony Resources Alert
To complete the upgrade process in this situation, you need to either:
 Remove the telephony channel definition that will not be in the upgraded project after the
transition from the TEL2 to the TEL1. Remove the channel by selecting it and clicking Remove, or
Polycom, Inc. 314