DTMF not working through our Webex hybrid devices. Spark-RD Device -> PSTN

[ed.gumuskaya]

DTMF not working through our hybrid devices.
MX300 registered to our CUCM using our Spark-RD device.
CUCM version 11.5.1(Su5)
Expressway 8.11

-MX300 dials 02034785289 (Cisco webex) -> Expressway-E -> Expressway-C -> CUCM -> MGCP Router -> PSTN.
--Call establishes
--No DTMF

-MX300 dials 8888 (VM Pilot) -> Expressway-E -> Expressway-C -> CUCM -> SIP ExchangeUM Voicemail
--Call establishes
--DTMF works

-DeskPhone dials 02034785289 -> CUCM -> MGCP Router -> PSTN.
--Call establishes
--DTMF

-Jabber MRA dials 02034785289 (Cisco webex) -> Expressway-E -> Expressway-C -> CUCM -> MGCP Router -> PSTN. (separate EXP environment)
--Call establishes
--DTMF works

We have registered a software and hardware MTP and assigned to Device pool of Spark-RD and EXP-C Trunk.

Please advise on how we get DTMF to work from a Spark-RD Board. We have three Spark-RD boards registered with the same symptoms. Our Spark-RD Webex Teams clients all have the same symptoms.

TAC advising that the workaround would be to upgrade to 12.0. This is not an option for us.

Other reported instances:

https://www.reddit.com/r/networking/comments/9is10z/webex_teams_is_down/       - Search DTMF post

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvj97289/?rfs=iqvred

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvb39142

[ed.gumuskaya]

DTMF is seen on the pcap between the Expressway-C to CUCM Sub as RFC 2833.

So must either be CUCM or MGCP not liking it. Can't see anything in the ccm/cti logs pulled from RTMT.

[ed.gumuskaya · Accepted solution]

RESOLVED: setting this on the gateway and forcing CUCM to use "Out-of-Band" on the gateway page.

#mgcp package-capability dtmf-package