Signalling & protocols – VoIP, SS7, ISDN and CAS

Aculab’s signalling protocol coverage extends to the broadest range of worldwide PSTN, call control, digital network access and E1/T1 signalling protocols for when you need an ISDN connection. The list also includes SIGTRAN and many variants of Signalling System No. 7 (SS7), ISDN and CAS protocols for operation over E1/T1 trunks. In addition, when you need just VoIP or IP telephony, Aculab offers VoIP protocols and SIP 2.0 stacks for use with Prosody X and Prosody S. A large number of the signalling protocols are also available for use with Aculab’s media gateway products, GroomerII and ApplianX.

  • Aculab’s Prosody X VoIP-based DSP boards using SIP 2.0 can also be combined with any PSTN signalling protocol, including ISDN, SS7 and CAS protocols, to deliver powerful, cost-effective telecoms solutions.
  • The ability to combine telephony board functionality with signalling protocols enables single card solutions, which are extremely cost-effective, compared to alternatives needing separate DSP and signalling cards.
  • Offering the same core VoIP or IP telephony functionality, Prosody S offers granular scalability and a viable, software-only, alternative to using telephony cards for SIP 2.0 in hosted, service provider or enterprise platforms.
  • Using a download utility, developers can simply download the signalling protocol firmware, free of charge, when they need it – a distinct advantage in system cost and value per channel.
  • Excluding SIGTRAN and dual redundant SIP, which are licensed, all signalling protocols, including SIP 2.0 and SS7, are freely available for use with Prosody X and Prosody S.
  • Aculab has obtained many country specific, host independent regulatory approvals, meaning Prosody X can be integrated into PC or server-based solutions without further telecom approvals being needed.
  • As part of its support and professional services value-add, Aculab can offer assistance to users seeking system level type approvals in regions where host independent approvals are not available.
  • Protocols for PSTN or ISDN connection, enabling deployment of a wide variety of global telephony solutions over E1/T1 trunks, include support for: QSIG; DPNSS; DASS2; NI-2; ETS300; and EuroISDN
  • Support for signalling system number 7 (SS7), includes: SIGTRAN M3UA; SCTP; many national and international variants of ISUP; SCCP; TCAP; and MTP2/3
  • Legacy CAS protocol support includes: T1 robbed bit (T1RBS); and many national and international variants of MRCR2
  • Protocols for VoIP or IP telephony, include support for: SIP 2.0; SIP RFC 3261; and SIPS (TLS)

SIP compatibility SIP from: AcmePacket; Avaya; BT; Cisco; Level 3; microDATA; Polycom; Siemens; SNOM; Voxbone – works with most other SIP solutions.

Important note: ApplianX and GroomerII media gateways use Aculab’s signalling protocols packaged into a single, version controlled software build, therefore, signalling protocols shall not be individually downloaded and installed in an ApplianX or a GroomerII. For information on ApplianX and GroomerII protocol support, please contact your Account Manager or email


  • Signalling & protocols – VoIP, SS7, ISDN and CAS
  • Signalling & protocols – VoIP, SS7, ISDN and CAS

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