Tieline Technologies


Tieline Leads with SIP Compliant Codec Development

Expand your SIP Capability

SIP (Session Initiation Protocol) is used extensively throughout the world by radio broadcasters to connect IP audio streams between different brands of IP codecs.

SIP provides superior interoperability due to its standardized protocols for connecting devices and is intended to be used when connecting Tieline codecs to non-Tieline codecs. Devices primarily use SIP to dial another device’s SIP address and find its location with a minimum of fuss. This task is usually performed by SIP servers, which communicate between SIP-compliant devices to set up a call.

Interest in SIP continues to build as broadcast networks around the world migrate from ISDN and POTS to IP for transporting audio streams. SIP is used extensively by many broadcast networks throughout Europe and other countries. As a result, Tieline has taken SIP development to a new level by supporting up to 6 simultaneous SIP connections in Genie Distribution and Merlin PLUS audio codecs. All from a 1U box!

All Tieline codecs can be configured to connect with both Tieline and non-Tieline SIP capable devices, so you can connect to different brands of codecs at different times as required. They also support mandatory EBU N/ACIP 3326 algorithms like G.711, G.722, MPEG-1 Layer 2 and 16 bit PCM. The Genie, Merlin and Bridge-IT* families of codecs also support SIP connections using optional EBU N/ACIP 3326 algorithms including LC-AAC, HE-AAC, AAC-LD, AAC-ELD and aptX® Enhanced.

How does SIP work?

There are two very distinct parts of a call when dialing over IP. The initial stage is the call setup stage and this is what SIP is used for. Data transfer occurs in the second stage and other protocols are used to perform this task (i.e. UDP to send audio data).

When connecting two devices using SIP, SDP (Session Description Protocol) performs similar tasks to Tieline’s proprietary session data, which is used to configure all non-SIP IP connections.

The following diagram displays an example of how you could configure a Merlin PLUS codec for up to 6 simultaneous remote broadcasts using SIP.

------ Merlin PLUS SIP Remotes


All Tieline Codecs Support SIP

The following table displays the number of connections possible over SIP from each Tieline IP codec.

Tieline Codec

No. SIP Cxns

Merlin PLUS**

Up to 6

Merlin PLUS with WheatNet-IP**

Up to 6


Up to 2

Genie Distribution**

Up to 6

Genie Distribution with WheatNet-IP**

Up to 6

Genie STL

Up to 2

Bridge-IT XTRA




Commander G3 Rack


Commander G3 Field Unit


i-Mix G3


* Bridge-IT Basic IP codecs require additional license upgrades to support AAC and aptX® Enhanced encoding. Bridge-IT Pro IP codecs require a license upgrade to support aptX® Enhanced encoding.

** Requires firmware release higher than v2.8.xx