> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/telecom-references/ss7-and-signalling/ss7/signaling-protocols.md).

# Signaling protocols

Signaling refers to the system of messages required to set up and tear down telephone calls between the calling and the called parties.

### TelcoBridges and Signaling Protocols

TelcoBridges' products not only multiple signaling protocols but also provides mediation between different protocol vendors.

**SBC**

* **IP**
  * [SIP](/telecom-references/sip-and-voip/sip.md) RFC 3261 User Agent, SIP Authentication
    * Access to SIP headers
    * Extensive SIP header manipulation
    * SIP to SIP-I protocol conversion
    * [SIP registration forwarding](https://telcobridges.com/learning/session-border-controller/softphone-and-the-sbc/), [SIP subscribe/notify/publish forwarding](/telecom-references/sip-and-voip/sip/sip-subscribe-notify-publish-forwarding.md)
    * NAT traversal

***T*****media**

* **PSTN**
  * [SS7](/telecom-references/ss7-and-signalling/ss7.md)/C7
    * (20+ variants) [MTP2](/telecom-references/ss7-and-signalling/mtp2.md), [MTP3](/telecom-references/ss7-and-signalling/mtp3.md) and [ISUP](/telecom-references/ss7-and-signalling/isup.md)
  * [ISDN](/telecom-references/ss7-and-signalling/isdn.md) PRI
    * (14+ variants), National ISDN-2, Euro ISDN, DMS100, DMS250, 4ESS, 5ESS, Japan INS-NET1500, NET5 (France, Germany, UK, China, Hong Kong, Korea), NTT
  * [CAS](/telecom-references/ss7-and-signalling/cas.md) (Script-oriented approach):
    * [CASR1](/telecom-references/ss7-and-signalling/cas/casr1-scripting.md):
      * E\&M "Wink start" or "Delay start"
      * [Loop start](/telecom-references/ss7-and-signalling/cas/cas-r1-loopstart-network.md) ([network side](/telecom-references/ss7-and-signalling/cas/cas-r1-loopstart-network.md) and [user side](/telecom-references/ss7-and-signalling/cas/cas-r1-loopstart-user.md))
      * ground start
    * [CASR2](/telecom-references/ss7-and-signalling/cas/cas-r2-scripting.md):
      * Generic (ITU base specification)
      * Brazil
      * Mexico
      * Venezuela
  * [H.248](/telecom-references/sip-and-voip/h248-mgcp.md#h248-package-support)
  * [GR-303](https://telcobridges.com/media-gateways/solutions/modernize-gr-303-networks/)
    * The integration of the GR-303 protocol for Tmedia enables a seamless interoperability between GR-303 and H.248 as well as GR-303 and SIP.
* **IP**
  * [SIP](/telecom-references/sip-and-voip/sip.md) RFC 3261 User Agent, SIP Authentication
    * Access to SIP headers
    * Extensive SIP header manipulation
    * SIP to SIP-I protocol conversion
    * NAT traversal
  * [SIGTRAN](/telecom-references/ss7-and-signalling/sigtran.md)
    * [M2UA](/telecom-references/ss7-and-signalling/sigtran/sigtran-m2ua.md), [M2PA](/telecom-references/ss7-and-signalling/sigtran/m2pa.md), [M3UA](/telecom-references/ss7-and-signalling/sigtran/m3ua.md) and [IUA](/telecom-references/ss7-and-signalling/sigtran/iua.md)

### Important Notes

* TelcoBridges Tmedia devices also offer the conversion (transcoding) of signaling messages between nodes that use different signaling protocols. For more information about Transcoding options, see TelcoBridges website.
* All supported protocols can be used simultaneously.


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