
Apples and Oranges: PBX Connector vs SIP Trunk Connector
We sometimes get asked to explain the difference between our PBX Connector and our SIP Trunk Connector. This post will compare both options to help you decide the best strategy to integrate your PBX or UCaaS with Microsoft Teams Phone System.
TeamMate offers two types of telephony integrations to Microsoft Teams: PBX Connector and SIP Trunk Connector. Each is designed to solve a different problem.
The PBX Connector maps a Teams User to a specific SIP extension on your PBX, thereby allowing you to extend the full functionality of your PBX to Teams. It essentially converts Teams into a softphone that’s registered to your PBX so that the core PBX features you currently offer – such as Call Parking, Call transfer, Busy Lamp Field (BLF), Message Waiting Indicator (MWI), among others (see here for more details about our advanced features) – work the same way as they would with any other SIP softphone. This product was created to let UCaaS providers give their end users that also use Teams the best of both worlds. In this use case, your PBX is supplying all of the call handling intelligence and Teams operates as a simple endpoint.
In contrast, the SIP Trunk Connector, also referred to as Direct Routing as a Service (DRaaS) allows you to route calls between a SIP gateway and Teams, and is typically used when your customer wants to use the Microsoft Teams Phone System as their primary feature server. Typically, this means that Auto-Attendants, Call Queues and other telephony features would be managed from the Teams admin center. This product was designed to automate the creation of direct routes for providers that want to sell SIP Trunking services to their clients that use Microsoft Phone System. In this use case, all calling features would be supplied by Microsoft and you would provide the SIP trunking service to interconnect with the PSTN.
Yes, it possible to use the SIP Trunk Connector to connect with a SIP Trunk pointed to the PBX or a UCaaS service. However, while this may enable basic calling functionality between both systems, you will lose many of the features that rely on the individually registered SIP extensions. Because a SIP Trunk creates a one-to-many relationship between the PBX (one) and Teams users (many), any PBX feature that relies on an authenticated user account will not work. This includes features such as Call Parking, BLF, MWI, and others. In order to make these PBX features work with Teams, the registration approach used by the TeamMate PBX Connector is what you need.
To compare apples to oranges and learn more about developing a strategy to integrate your PBX or UCaas service with Microsoft Teams, check out this informative blog from industry expert Jon Arnold, see a comparison of 3 Ways to Integrate your UCaaS with MS Teams, or download our white-paper on that subject here.
Frequently asked questions
What is the difference between PBX Connector and SIP Trunk Connector?
PBX Connector maps each Teams user to a SIP extension on the PBX, so Teams works like a softphone registered to the PBX and the PBX supplies the call handling. SIP Trunk Connector, also called Direct Routing as a Service, routes calls between a SIP gateway and Teams when Teams Phone is the main feature server.
Which PBX features work in Teams with PBX Connector?
Because each Teams user registers as an individual extension, core PBX features such as call park, call transfer, busy lamp field (BLF) and message waiting indicator (MWI) work the same way they do on any SIP softphone. Call flows keep running on the PBX, and PBX Connector supports 80+ PBX types.
Can I connect my PBX to Teams with a SIP trunk instead?
You can, but you will only get basic calling between the systems. A SIP trunk creates a one-to-many relationship between the PBX and Teams users, so any feature that relies on an authenticated user account, such as call park, BLF and MWI, won't work. PBX Connector's per-user registration is what keeps those features.
When should a provider use SIP Trunk Connector?
Use SIP Trunk Connector when the customer wants Microsoft Teams Phone as its primary phone system, with auto attendants, call queues and other features managed in the Teams admin center. The provider supplies SIP trunking to the PSTN, and the connector automates creating the direct routes.


