I have recently upgraded CUCM 6.1(3) to the latest patch and since then I am unable to get tone on hold working correctly.
Tone on hold works internally if you call IP Phone to IP Phone but if you put an external caller on hold they get silence.
I have h323 gateways and have checked that the send user H225 info message is set to User Info for Call Progress Tone and I have checked that the progress indicators are set correctly on the gateway (even though it worked before the upgrade and there have been no changes to the gateway).
If I enable MoH, it works fine but when I turn it off again I still get silence instead of the tone.
Does anyone have any other suggestions as to what it could be?