Yeastar S-Series PBX, U-Series and TG Series Gateway supports use external SMTP server and POP3 server to reset the password, send voicemail to email, send alert event emails, send the fax to email, send SMS to Email, and send Email to SMS.
The basic work flow of SMS to Email:
1. Firstly, Yeastar device would receive SMS by GSM module: SMS work flow
2. Then Yeastar device would send email with content of received SMS.
Here is the standard SMTP protocol communication flow between the S-series PBX and the SMTP Server.