Scalable and Modular S-Series VoIP PBX

scalable ippbx

Yeastar S-Series VoIP PBX provides flexible telephony interfaces combination while allowing for future scalability with unique modular design. Besides the built-in rich SIP capabilities, S-Series lets you decide what types of extensions and physical trunks you need in your telephone system. When your business grows, adding more users and concurrent calls is also possible with S-Series.

Add Telephony Interfaces

With Yeastar S-Series, all the telephony interfaces are modular and customizable, whether it’s FXS, FXO, ISDN BRI, GSM/3G, or E1/T1/PRI. S20 has 2 onboard module slots, S50 and S412 supports 4. S100 and S300 require the combination of Expansion Board and Telephony Module to add telephony interfaces. S100 allows 2 Expansion Boards and S300 supports 3.

Techology Interfaces

Telephony Modules Available

Supported Model: S412, S20, S50, S100, S300

S2 Module

Module S2

2 FXS Ports

Add 2 analog telephones.


O2 Module

Module O2

2 FXO Ports

Connect 2 analog PSTN (POTS) lines.


SO Module

Module SO

1 FXS Port & 1 FXO Port

Unique PSTN Fallback Function


B2 Module

Module B2

2 BRI Ports

2 x NT/TE BRI Ports


GSM Module

Module GSM

1 GSM Channel

1 Channel for GSM Voice Calls Frequency: 850/900/1800/1900 MHz (quad-band)


3G Module

Module GSM

1 WCDMA Channel

1 Channel for WCDMA Voice Calls Frequency: 900/2100 MHz, 850/2100 MHz, 850/1900 MHz


4G LTE Module

Module 4GLIE

3G/4G Voice Call & Data

Insert 4G module on Slot_1 of S20&S50 and Slot_1 of EXP 1 of S100&S300.Learn more.


Expansion Board


EX08 has 4 onboard module slots and 8 interfaces on the panel.
Supported Model: S100 and S300


EX30 has 1 onboard E1/T1/PRI port.
Supported Model: S100 and S300


Expand System Capacity

D30 Module

Add 100 VoIP Users & 30 Concurrent Calls
Supported Model: S100 and S300

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