Add a coma between the phone number and the extension. It worked for me using Jabber on Windows v11.0.1 and CUCM v9.1.2.
e.g:915551234578,100 for extension 100.
Does anyone know the minimum Jabber + CUCM software versions that are needed to make this work? We are using Jabber 10.6.3 and CUCM 8.6.2. The comma delimiter is interpreted as a multi-number conference call on this combination of releases. e.g. 5551212, 1000 is processed by Jabber as a call to 5551212 and a call to 1000--as if you are wanting to bridge the two numbers into a conference call.
I don't know about the Jabber version required but the "Pause in Speed Dial" feature is new to CUCM 9.x.
Release notes here:
More details and examples here:
It's not working because this requires Jabber 11.x, this is not included in any previous Jabber version.