Grandstream UCM

Asterisk-based appliance with a five-file default hold class.

MakerGrandstream Networks

What callers hearA five-file default class (probably the Asterisk set, unconfirmed)

Confidencelow

Listen for

If it's one of the five Asterisk tracks, Asterisk-based boxes like this one are the likely source

Grandstream’s UCM6xxx appliances are built on Asterisk. The manual says the “default” music-on-hold class comes with five audio files, the same count as stock Asterisk. We couldn’t confirm they’re the same five opsound tracks, so we’re not claiming it.

If you recognize a track from the Asterisk page, a Grandstream UCM is one of several possible sources.

Sources

Grandstream UCM6300 user manual (PDF)