Stay Connected. Anywhere. Anytime.

Reliable communications, wherever you are.

When Every Call Matters

Callisto Calling Client is a professional SIP softphone for Android designed to keep teams connected wherever their work takes them. From corporate offices and remote locations to cruise ships and operational environments, Callisto delivers reliable voice and video communication when every conversation matters.

Built for organizations that depend on continuous connectivity, Callisto combines native SIP calling with seamless access to corporate directories, voicemail, contact information, and call recordings, all within one intuitive application.

Whether users are coordinating daily operations, supporting colleagues, or managing critical communications, Callisto provides the reliability and flexibility needed to stay connected anytime, anywhere.

Callisto Calling Client

Reliable communications for mobile teams, remote workers, and mission-critical operations

  • Overview
  • Features
  • Services
  • References

Highlights

Reliable Calling

Reliable incoming call availability, even when mobile devices enter power-saving modes. Stay reachable with dependable voice and video communications designed for uninterrupted availability.

Native SIP Integration

Connect seamlessly to your existing SIP-based Unified Communications platform without changing your infrastructure.

Unified Communication Experience

Access calling, corporate directory, voicemail, contact photos, and recordings from one intuitive application.

Never Miss a Call

Enable reliable communications across offices, remote locations, and onboard environments.

All features in detail

Features from A–Z Description
ProfIVR
AI Voicebot		 This feature enables automated, intelligent customer interactions
ProfIVR
AI Call Summarization and Transcription		 Automatically generates call summaries and transcripts for efficient documentation and record-keeping
ProfACD
AI Call Summary		 Provides live agents with an instant conversation summary and all information collected by the Voicebot upon call transfer
ProfACD
AI Silent Monitoring		 Provides real-time call transcription and summarization, enabling agents and supervisors to monitor live interactions more effectively

We support you in every situation

Sales Support

We support you in every step of the resale cycle. Depending on your Partner level, we will guide you through the sales process with your customer.

Installation and Configuration Support

We support you during the installation, configuration, and roll-out process for on-prem, managed service, or cloud projects. A satisfied partner and customer is our daily goal.

Operation and Maintenance Support

We pay attention to the highest quality and stability in each phase of our product development process. Our dedicated support team is immediately available according to defined SLA times if any incident still occurs. More…

Training

We train and support our partners and their customers to learn how to correctly install, manage and use our Callisto products. More…

Tailored Developments

Thanks to the unique Callisto “Open Applications Management” concept, partners and their customers can add customized and tailored applications to the system anytime during runtime with no service interruption. More…

Consulting

Our long-lasting expertise in UCC services and comprehensive industry know-how lead CTModule to deliver the best-in-class consultancy for your projects. More…

You can expect only the best – Because quality matters

Compatible

The Callisto appliance solution has been successfully tested and certified with Cisco UCM. In addition to that, the Callisto platform is compatible with all popular Cisco PBX systems (UCM, UCME, BE6k/7k, HCS, Webex).

Preferred Solution Partner

CTModule has been working with Cisco Systems since 2004 and is now one of the selected manufacturers worldwide with the Cisco Preferred Solution Partner status.

Compatible

Callisto is compatible with Mitel systems.

Compatible

Callisto is compatible with the InForm Voice platform.

Callisto Calling Client – Your best choice

Reliable

Stay reachable with dependable voice and video communications designed for environments where every call matters, without relying on external push notifications.

Intuitive

Enjoy a simple mobile experience combining calling, corporate directory, voicemail, and recordings in one application.

Integrated

Seamlessly connects with your existing Callisto Unified Communications platform while bringing essential communication services together in one application.

Why Callisto Calling Client?

Business communication should be effortless. You shouldn’t have to wonder whether your phone will ring when someone calls.
Many mobile communication apps rely on cloud push notifications or background services that can be affected by Android’s power-saving features. As devices enter sleep mode, background network activity may be restricted, potentially delaying or preventing incoming VoIP calls until the application wakes again.

Callisto Calling Client was designed with reliability in mind.
Instead of depending solely on external notification services, it provides a communication architecture built for environments where every call matters.

Whether you’re connected through corporate Wi-Fi, or onboard connectivity at sea, Callisto helps ensure you’re always ready for the next conversation.

Built Around the Way You Work

Communication is more than simply making a call. Throughout the day, users need to switch between conversations, transfer calls, consult colleagues, access contact information, and quickly reach the right person.

Callisto Calling Client brings these everyday tasks together in a clean, intuitive interface that feels familiar from the very first call. Multi-call handling, conference calls, intelligent call routing, voicemail, recent calls, and contact history are all integrated to keep conversations flowing without unnecessary complexity.

Whether you’re coordinating operations across departments, assisting colleagues, or responding to operational requests, Callisto helps you stay focused on the conversation, not the technology.

Your Directory, Always Within Reach

Finding the right colleague should never slow you down.

Callisto integrates directly with your corporate directory, providing fast search, complete contact details, company information, photos, and call history in one place. Predictive T9 dialing, favorites, and speed dial shortcuts make frequently contacted colleagues only a few taps away.

Everything is designed to reduce the time between finding a contact and starting a conversation.

Secure by Design

Callisto Calling Client integrates seamlessly with Cisco Unified Communications Manager, Mitel MiVoice, and other standards-based SIP platforms, supporting on-premises, cloud, and hybrid deployments.

With secure TLS connections, support for custom and self-signed certificates, encrypted credential storage, and failover capabilities, Callisto provides the flexibility and security organizations need to communicate with confidence.

Choose the Edition That Fits Your Organization

Callisto Calling Client Basic

The Basic edition provides everything users need for professional day-to-day communication.

  • Audio and video SIP calling
  • Call recording
  • Voicemail integration
  • Corporate directory and contact management
  • Recent calls and call history
  • Multi-call handling
  • Conference calling
  • Call transfer and forwarding
  • Speed dial and T9 search
  • Secure and reliable SIP connectivity

It is the ideal choice for crew members, office staff, supervisors, healthcare professionals, hospitality employees, and anyone who relies on dependable business communications.

Callisto Calling Client Advanced

The Advanced edition includes all features of the Basic edition, plus:

  • Automatic Call Distribution (ProfACD)
  • Call queuing
  • Agent-ready call handling
  • Optimized workflows for service and support teams

Designed for call centers, guest services, help desks, and other teams that manage high volumes of incoming calls while delivering efficient and responsive service.

Technology that inspires

  • Architecture
  • Requirements
  • Compatibility

Callisto architecture – The new simplicity

The Callisto platform provides the following features (without Modules and Applications):

  • all interfaces to the Cisco telephony infrastructure, provisioning (e.g., Kurmi), and 3rd party systems (e.g. (S)PMS, CRM, alarm systems, etc.)
  • Base infrastructure for import, configuration, and administration of modules, collections, and applications
  • Platform management for security, back-up/restore, update/upgrade process, licensing, log and troubleshooting capabilities
  • Dashboard and reporting
  • Single Sign-On (SSO) support
  • User and administrator management, rights management.

After licensing, modules, collections, or customized applications can be uploaded to the Callisto platform and configured in a simple and flexible way.
Callisto, with its available modules and applications, supports the following end devices and clients (depending on the use case):

  • Callisto web and telephone interface
  • Cisco endpoints (XML-enabled with push message support)
  • Cisco Jabber client with Callisto Gadgets (tabs)
  • Cisco Webex App
  • PC with Callisto operator solution and Callisto Gadgets
  • SmartPhones (iOS/Android) with Callisto Gadgets and native applications
  • Tablets (iOS/Android) with Callisto Gadgets and native applications
  • Legacy phones, DECT phones, WLAN phones according to manuals.

The Cisco PBX infrastructure (BExk, UCM, HCS) is connected to the Callisto platform via SIP trunk, AXL, and JTAPI (for COC switch solution) or SFTP (for CDRs).
Further Callisto interfaces are:

  • SIP, Secure SIP (UDP, TCP, TLS)
  • RTP, SRTP, T.38/G.711 (Softfax)
  • Cisco AXL
  • IP Socket connection
  • HTTP(S), (S)FTP
  • (S)LDAP (authentication, phone book)
  • ESPA 4.4.4 / X (Alarming)
  • REST (provisioning)
  • Application interfaces for various services or applications

The Unified Presence Server (CUPS) can be integrated as an external presence source.

Minimal requirements and resource-saving for green IT

The following requirements are needed for a proper use of the Callisto platform with the selected module(s):

Requirements Requisite/Description
Callisto Appliance (virtual Image, OVA)
  • One Callisto appliance for up to approx. 1000 parallel calls on the platform.
  • One platform is sufficient for an unlimited number of users and voicemail boxes
Virtual environment minimal: VMware ESX(i) 6.7
Callisto Appliance “Small”
  • up to 60 parallel calls
  • 2 GB RAM
  • 2 CPUs (ca. 2 GHz)
  • 80 GB hard disk space
  • 1 network connection
Callisto Appliance “Medium”
  • up to 240 parallel calls
  • 4 GB RAM
  • 4 CPUs (ca. 2 GHz)
  • 80 GB hard disk space
  • 1 network connection
Callisto Appliance “Large”
  • starting from 240 parallel calls
  • 6 GB RAM
  • 8 CPUs (ca. 2 GHz)
  • 80 GB hard disk space
  • 1 network connection
  • max. 960 parallel calls per appliance
PBX (TVA/PBX) Cisco IP-PBX: CUCM, HCS, Webex (Unified CM), BExk, UCx00

Compatibility

The following products have been tested for interoperability with the Callisto platform.

Note: Various modules of the Callisto platform may also be compatible with other IP-PBX systems. Contact us if you have a specific project.

Manufacturer System Version
Cisco Systems Inc. Unified Communications Manager 7.x, 8.x, 9.x, 10.x, 11.x, 12.x, 14.x
Cisco Systems Inc. Unified Communications Manager Business Edition 6000 8.6, 9.x, 10.x, 11.x, 12.x, 14.x
Cisco Systems Inc. Unified Communications Manager Business Edition 7000 8.6, 9.x, 10.x, 11.x, 12.x, 14.x
Cisco Systems Inc. Hosted Collaboration Solution (HCS) 8.6, 9.x, 10.x, 11.x ,12.x, 14.x
Cisco Systems Inc. Cisco UCM Cloud —
     
Cisco Systems Inc. Cisco Unified Presence Service (CUPS) 8.x, 9.x, 10.x, 11.x, 12.x, 14.x
     
Cisco Systems Inc. Cisco Jabber 7.x, 8.x, 9.x, 10.x, 11.x, 12.x, 14.x
Cisco Systems Inc. Cisco Webex Client —
     
Diverse Android for Smartphones and Tablets upon request
Apple Inc. IOS for Smartphones and Tablets upon request
     
CTModule AG COC Operator Console Windows 7.x, 8.x, 10.x, 11.x

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We are happy to assist you

Phone: +41 31 531 11 11
Email: sales@ctmodule.com