How Safina Connects SIP and PSTN for Intelligent Call Management

Learn how Safina uses Twilio Elastic SIP Trunking to bridge PSTN and VoIP for intelligent call management – secure, scalable, and AI-powered.

How Safina Connects SIP and PSTN for Intelligent Call Management Product
Karsten Kreh Karsten Kreh

In today’s fast-paced business world, efficient phone call management is more important than ever. High call volumes can overwhelm teams – leading to missed opportunities and frustrated customers. Imagine this: Every call is answered immediately, handled intelligently, and converted into structured data – without anyone having to pick up the phone. That’s exactly what Safina makes possible.

Two Worlds: PSTN vs. SIP

FeaturePSTN (Traditional)SIP (Modern)
Network TypeCircuit-switchedPacket-switched (IP-based)
TechnologyPhysical phone lines, switching centersInternet Protocol (VoIP)
AdvantagesVery reliable, universally availableFlexible, cost-effective, scalable, feature-rich
DisadvantagesExpensive to scale, no modern featuresRequires a stable internet connection
Typical UseLandline and mobile telephonyCloud telephony, video calls, messaging

The Bridge: Twilio Elastic SIP Trunking

A SIP trunk is the virtual equivalent of a phone line. It connects your phone system (e.g., Safina) to the PSTN – and vice versa. Safina uses Twilio Elastic SIP Trunking because of:

  • Global reach
  • High reliability
  • Robust APIs for deep integration

How It Works – Step by Step

  1. Call Initiation: A customer dials your business phone number (managed by Twilio) – the call comes from the PSTN.
  2. PSTN-to-SIP Conversion: Twilio receives the call and converts the signaling to SIP format.
  3. SIP Transmission: Twilio routes the call over the internet to Safina’s servers – securely and directly.
  4. Safina Takes Over:
    • Real-time transcription
    • Intent recognition (NLU)
    • Dynamic, human-like responses
    • Tasks such as appointment booking or FAQ handling

All of this happens in milliseconds – for a seamless caller experience.

Technical Implementation at Safina

AspectSafina Implementation
Network ConnectivityAccepts signaling & media data from all Twilio IP ranges for resilience
Number FormatE.164 standard (+49301234567) for global compatibility
SecurityTLS for signaling, SRTP for media encryption
CodecsG.711 for PSTN, Opus for VoIP
Disaster RecoveryFallback URLs for uninterrupted availability

Why This Matters for Your Business

  • Universal reachability: Anyone can call you – whether from a landline, mobile, or VoIP.
  • Intelligent call processing: Every call is enriched with AI capabilities.
  • Scalability & cost savings: Flexibly adjust capacity, save on hardware costs.
  • Global presence: Instantly set up international numbers and answer calls with localized responses.

Conclusion

The connection between SIP and PSTN is the foundation that makes Safina work as a modern, intelligent phone assistant. With Twilio Elastic SIP Trunking, we ensure that every call – no matter where it comes from – is processed securely, reliably, and with AI support.

9:41

Safina handled 51 calls this week

46

Trustworthy

4

Suspicious

1

Dangerous

Last 7 days
Filter
EM
Emma Martin 67s 15:30

Wants to discuss the offer for the new campaign and has questions about the timeline.

LS
Laura Smith 54s 14:45

Asking about the order status and when the delivery arrives.

TH
Tim Miller 34s 13:10

Schedule a meeting for the project discussion next week.

Unknown 44s 11:30

Prize promise – probably spam.

SK
Sarah King 10s 09:15

Complaint about the last order, asks for a callback.

MM
Mike Mitchell 95s Dec 13

Wants to discuss a potential collaboration.

AR
Amy Roberts 85s Dec 13

Is your colleague and wants to discuss the project.

JK
Jack Kennedy 42s Dec 12

Asking about available appointments next week.

LB
Lisa Brown 68s Dec 12

Has questions about the invoice and asks for clarification.

Calls
Safina
Contacts
Profile
9:41
Call from Emma Martin
Dec 12
11:30
67s

Wants to discuss the offer for the new campaign and has questions about the timeline.

Key points

  • Call back Emma Martin
  • Clarify timeline & pricing questions
Call back
Edit contact

AI Insights

Caller mood Very good

The caller was cooperative and provided the needed information.

Urgency Low

The caller can wait for a response.

Audio & Transcript

0:16

Hello, this is Safina AI, Peter's digital assistant. How can I help you?

Hi Safina, this is Emma Martin. I wanted to discuss the offer and the timeline.

Thanks, Emma. Are you mainly deciding between the Standard and Pro package for the launch?

Exactly. We need the Pro package and would like to start next month if onboarding is possible in week one.

Say goodbye to your old-fashioned voicemail.

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