1 E1/T1 Port Expansion Board for Yeastar S100 and S300 systems Add up to 2 boards to S100 and up to 3 to S300

Expansion Board for Yeastar S100 and S300 systems Supports up to 4 optional modules/8 ports, including O2, S2, GSM and LTE modules
Adds 2 expansion cards to S100 and 3 to the S300

Expands capacity by 100 extensions and 30 concurrent calls.
1 module on the S100 and up to 2 modules on the S300