after reading alot of docs about DSP and transcoding and MTP, im confused. lets talk about most real scenario. i have 2 call manager 7835 and media service activated. i have also 2 2821 router with E1 Card each. users around 600 cisco ip phones and 120 3rd party sip phones. do we need DSP resources to call over ISDN.?? we are signle site no transcoding or .. h323 endpoint. does the Cisco 2821 embeded built with one DSP ??? i mean no need to buy another PVDM? i know 2821 can have up 2 3PVDM.
and incase i want to configure a transcoder and enhaced conferencing on the router , will enable SCCP , but also i want to use it AS MGCP gateway with E1 connected to PSTN? so can both SCCP and MGCP be active at the same time? SCCP for enhaced conf and transcoding and MGCP to control ISDN and FXO?