Yeastar Technology P550 - Install Yeastar P570 Expansion Board; Expansion Board Installation Steps

Installation Guide | 3 - Install PBX | 25
4. Lock the screws to fix the Expansion Board.
5. Insert the Telephony Modules on the EX08 Board.
Note: Skip this step for EX30 Board.
6. Follow the instructions to insert a SIM card on the GSM/3G/4G LTE module.
Note: Skip this step if no GSM/3G/4G LTE module is installed.