Yeastar O2 Module (2FXO) – YST-O2

• Expansion module with 2 FXO (Foreign Exchange Office) ports designed to add analog PSTN connectivity to compatible Yeastar VoIP gateways and PBX systems

• Allows easy integration of traditional analog telephone lines (PSTN) into modern VoIP/IP-PBX environments

• Enables calls between your VoIP phone system and the public switched telephone network using standard analog trunks

• Ideal for businesses that still need to use existing landline/PSTN services alongside VoIP telephony

• Supports two separate PSTN lines, making it suitable for small office voice traffic or backup circuits

• Seamless plug-and-play installation into compatible Yeastar hardware with module slots

• Full support for standard telephony signaling and tone detection for reliable call handling

• Works with Yeastar VoIP Gateways and PBX systems that support modular expansions

• Integrated into the system’s routing and dial plans for unified call management

• No separate power required — powered through the host device once installed

• Compatible with router, least cost routing (LCR), and call routing rules defined on the host VoIP system

• Provides clear voice quality and stable connection for analog PSTN lines

• Helps businesses transition gradually from legacy landline infrastructure to VoIP

The Yeastar O2 Module (2FXO) – YST-O2 is a practical expansion module that adds two FXO ports to compatible Yeastar VoIP gateways and PBX systems, allowing integration of traditional analog telephone lines (PSTN) into a unified VoIP telephony environment. This module is ideal for small and medium-sized businesses that need to retain existing landline connectivity while modernizing their communications. With two separate PSTN interfaces, seamless installation, full PSTN signaling support, and integration with call routing and least cost routing features of the host system, the YST-O2 module offers a reliable and efficient way to bridge analog and IP telephony. It’s especially useful for businesses transitioning gradually to VoIP without abandoning their legacy phone lines.