The System Trunk Interface eXtender (STIX) FXS module is an FXS interface card that supports up to eight FXS channels. Each port provides 2 REN (Ring Equivalence Number) channels per line.
The 8-channel FXS interface card is for the connection of on-premises analog telephony devices only. It shall not be connected to external exposed line plant and telecommunications networks.
STIX-8FXS/DSP Connector Pinouts
4 and 3
2 and 5