I do not do much with CUCM Express so would appreciate some help with the following.
Is there any licensing requirement on CallManager Express for connecting to the PSTN via a SIP trunk? (thinking that there should be if you need CUBE licenses to connect CUCM to a SIP provider).
Is there a DSP requirement for SIP trunking? If I use G.711 between IP phones and G.729 to the SIP provider will I need DSPs for transcoding?