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Discover a comprehensive Solutions Center hub with resources, documentation, and expert guidance for all your business communication needs.

Access our dedicated customer service team around the clock, every day of the year. Get immediate assistance when you need it most.

Stay informed with real-time service updates, maintenance alerts, and important system notifications to keep your business running smoothly.

Monitor live system performance updates and network health metrics to ensure optimal communication service delivery across all platforms.

Technical support escalation for critical issues

Project implementation and deployment issues

Sales inquiries and contract negotiations

Billing disputes and account management

Strategic account growth and optimization

There is no better relationship in the industry than ones CallTower has with its partners. Here are just a few things that make working with us truly awesome.

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At CallTower, we consider our channel partners as family, valuing successful relationships through excellent support and financial rewards.

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Discover Are benefits of our Agency Partner Program for your business. Unlock revenue streams, scalable growth, and extensive support.

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CallTower's MSP Partner Program empowers service providers by simplifying taxation and enhancing efficiency through tools including the GTx self-service platform.

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Fax / MasterFax Overview

MasterFax: Product Overview


MasterFax is based on the Faxback fax server and an HTTPS-enabled Master Fax Adapter.

Rather than a traditional approach of requiring solid IP and a SIP connexion all the way to the MasterFax Adapter, this
replaces the link between the MasterFax Adapter and us with an HTTPS connexion. This connexion is not subject to the same
concerns with jitter and latency as SIP, which provides reliable faxing over unreliable IP.


Inbound Fax

  1. The remote fax machine sends the fax to the fax server over SIP.
  2. The fax server receives the fax and forwards it over HTTPS to the MasterFax Adapter.
  3. The Adapter plays back the fax to the customer fax machine via the analogue port.

Outbound Fax

  1. The customer’s fax machine sends the fax to the MasterFax Adapter via the analogue port.
  2. The Adapter forwards the fax to the fax server over HTTPS.
  3. The fax server sends the fax to the remote destination over SIP.

Customer Experience

  • The process ensures reliable faxing over IP, addressing concerns with jitter and latency.
  • Customers experience faxing as they always have, with no noticeable changes.
MasterFax - Overview
MasterFax - Overview

Fax / MasterFax Overview