Insert pause in outbound dialing

I’m trying to send *67 pause 18168228220 (or any phone number) to the carrier but I can’t figure out how to insert the pause.

I tried using the dial pattern in the outbound route with no luck. Any idea how to insert a pause in the middle of an outbound number?

I’m using SIP trunks that are talking to a Grandstream FXO gateway if that helps.

Which channel technology? This would seem a strange requirement from the provider for VoIP, a called numbers are normally sent in the request URI.

I’d imagine you would need to dial it as though the complete phone number was *67, and you then sent the remainder as (early media) DTMF. I thought there was a GUI way of doing this, but a quick search only comes up custom dialplan:

In any case, I think you need to ask the provider exactly what they require over the wire.

If this is analogue, you should be able to use the standard DTMF sending pause codes.