Solutions For Equipment Vendors

If you are an equipment vendor that sells communications products for PSAPs or other call center type organizations, Voiceriver has the technical solutions you need to add a higher level of accessibility to your products.  Listed below are some of the accessibility solutions we offer.


To accommodate the changes coming in Next Generation 9-1-1 (NG9-1-1), Voiceriver has created a "Legacy PSAP Gateway," which is a network appliance for use as a demarcation point between the PSAP and the Emergency Services IP Network (ESInet) provider.  This gateway converts protocols & media types as needed between the ESInet and PSAP to ensure interoperability and robust call handling. 

In the past, emergency calls were voice calls delivered to the PSAP over phone trunk lines.  NG9-1-1 expands the types of calls to include text messaging and other new technologies.  The vision for NG9-1-1 involves the use of an Internet Protocol (IP) based network.  In this architecture, emergency calls of all types are delivered to an IP-based PSAP as Voice over IP (VoIP) calls.  

It is anticipated that the implementation of NG9-1-1 will see the IP-based networks implemented prior to the PSAPs updating their equipment. In order to maintain consistency in functionality throughout the upgrade process, a new functional element, called a "Legacy PSAP Gateway" is used to make the new N9-1-1 IP-based network look like the legacy 9-1-1 network to the PSAP equipment.  (The gateway provides the analog phone trunks (CAMA) and RS232 Interfaces required to service caller location (ALI) database lookup.)  

Let Voiceriver show you how their "Legacy PSAP Gateway" simplifies the challenges of Next Generation 9-1-1 implementation.     


SMS-to-911 is also known as Text-to-911.  Voiceriver has developed a carrier-grade hardware appliance that easily fills the functionality needed for SMS-to-911 TTY Gateway.  Our product is an XMPP controlled gateway platform that connects between TDM (T1) and IP-based networks.  The system's TDM side is configurable to support up to 32 T1 lines in a single chassis.  

Utilizing digital signal processing (DSP) for audio handling, it can also be configured as a high capacity DSP based TTY modem bank capable of supporting up to 768 simultaneous modem connections in a single chassis.  

This platform has been proven in production use.  Contact us and let us show you how Voiceriver can implement a SMS-to-911 TTY Gateway in your communications environment.  


Voiceriver has developed a SIP endpoint toolkit that's available for developers.  This is a Software Development Kit (SDK) style toolkit and can be used to great advantage by developers needing to create a TTY or phone endpoint in a SIP (VoIP) environment.  The toolkit enables an IP-based application to be written that has the ability to participate in a phone call with a physical TTY machine as the opposite endpoint.

The SDK is a combination of a Baudot soft-modem together with a full SIP stack implemented in a “C” style DLL interface.  The run-time component for the API is packaged in a single windows “DLL” file.  This DLL has no external dependencies on third-party software, only standard windows libraries.   This toolkit is known as "ipTTY SDK" and is sold by Tenacity, a company that provides accessibility products.  

 Learn more about ipTTY SDK >


Voiceriver has developed our own state-of-the-art modem algorithms that support TTY-based text communications.  Written in ANSI-C, these algorithms have very low memory and processing requirements and are highly portable across platforms and architectures.  Unlike other implementations, our algorithms do not require a clocking source, as clocking information is derived from the audio stream itself.  This allows our algorithms to be used in both real-time and offline modes of operation

Our modem algorithms have been running in production implementations for years with tried and proven accuracy and reliability.  Voiceriver modem algorithms support the following protocols:

Deaf Protocols:

  • Baudot (45.45, 47, & 50 baud modes) compliant with TIA-825a
  • Turbocode®
  • E-Turbo™

V.series Protocols:

  • V.21 thru V.92
    (NOTE: The V.series modem standards are supported through Voiceriver's DSP platform.)