This guide will enable you to configure your OpenScape 4000 (OS4K) to pass calls to the Voice AI system and provide configuration to enable the calls to be returned (if applicable with a contact centre (CC) platform). On OS4K the trunk to Voice AI is a Session Initiation Protocol (SIP) trunk profile on a SIP trunk gateway board (vHG 3500), with a Session Border Controller (SBC) between the board and the Voice AI service. This configuration is done in the OS4K Assistant (the OpenScape 4000 management web application), the gateway board's web interface and the switch, using Administration and Maintenance Order (AMO) commands or the matching Assistant forms.
<aside> ⚠️
This guide covers the Voice AI trunk only. It assumes the following are already in place: an SBC with a working link to the Voice AI service (see the SBC requirements section below), a dedicated SIP trunk gateway board for Voice AI that shows READY in Gateway Manager (if you do not have one, see Add a SIP trunk gateway board for Voice AI below), and the board's internal IP address reachable from the SBC. Any carrier or Public Switched Telephone Network (PSTN) trunk is configured separately and is not covered here.
</aside>
<aside> ⚠️
This guide uses the NatTrkWithRegistration SIP trunk profile. Despite the name, "Use Registrar" stays unticked, so the board does not register: it authenticates with the account and sends calls to the SBC. The profile does not accept SIP REFER, which Voice AI uses to transfer calls back to your phone system, until you tick REFER Allowed (see the profile settings table below). Only one profile can be active on a board.
</aside>
Mitel advises using a separate gateway board for the Voice AI trunk. On an existing OS4K most boards are already in use for other trunks. If you already have a spare SIP trunk gateway board that is not used by anything else, skip to the next section.
You need the following before you start.
| Item | Details |
|---|---|
| A free slot | An unused slot in a unit (the second and third numbers of the PEN). In the Assistant, open Configuration Management → System Data → Maintenance → Board Maintenance and search: free slots show a status of NOGEN, NPR or UNACH. You can also check with the AMO DIS-BCSU. |
| An IP address for the board | An unused internal (private) IP address on the same network as the OS4K, reachable from the SBC. It is not a public address. If your OS4K runs on a virtual or cloud platform, the address must also be added to the platform's network interface (on AWS, as a secondary private IP address). |
| A gateway number | An unused number, for example 160. |
| A channel count | The number of simultaneous calls the trunk can carry. It cannot be changed later without removing and re-adding the board, so allow room to grow. For example, 30. |
| A function block | A function block (a definition of what the board can do and how many channels it has) that provides SIP trunk channels. Use an existing one, or create one in step 0 below. |
| A board password | The password for the board's service login. |
| A trunk group number | An unused trunk group number. Calls are routed to the trunk group, and it holds the board's trunk circuits. |
| Existing class numbers | The class of trunk (COT), class of parameters (COP) and class of service (COS) numbers that your other native SIP trunks use, and the node number of your OpenScape 4000. |
Adding the board takes four stages. AMO names such as BCSU, CGWB and GKREG are command names and are typed as shown.
After that you save and restart the board. It then shows READY in Gateway Manager and is ready for the trunk profile and the trunk circuits.
Before you start, save the system with EXE-UPDAT:BP,ALL; and wait for EXEC COMPLETED. Run the commands one at a time and read each response. A refused AMO changes nothing, so you can correct the value and run it again.
<aside> ⚠️
Values in angle brackets are yours to choose, using the checklist above. The other values are standard settings from Mitel's reference (Sandbox) configuration, and they match published native SIP trunk examples where we could check them. Leave them as shown unless your OS4K administrator advises otherwise.
</aside>
A function block tells the switch what a gateway board can do and how many channels it has. Check whether a suitable one already exists. If not, create one in the Assistant under Configuration Management → System Data → Board → CGW Function Block (CGW stands for Common Gateway): search for a free number, then select New. Or use the AMOs below, which are an example from Mitel's documentation.