You really need to check your resource requirement with the dsp calculator tool- does that give you any errors?:
http://www.cisco.com/cgi-bin/Support/DSP/dsp-calc.pl
I think there are some limitations for the 2801 and conferencing, I will look for that. I am pretty sure analog ports also preallocate resources, and those are not shared, but since you have 2 dsps, and only 2 ports, I think the two voice ports should stay on one of them, and leave the other available. Here is something from the SRND:
Hardware Audio Conference Bridge (Cisco NM-HDV2, NM-HD-1V/2V/2VE, 2800 Series, and 3800 Series Routers)
DSPs that are configured through Cisco IOS as conference resources will load firmware into the DSPs that is specific to conferencing functionality only, and these DSPs cannot be used for any other media feature.
The following guidelines and considerations apply to these DSP resources:
?Based on the C5510 DSP chipset, the NM-HDV2 and the router chassis use the PVDM2 modules for providing DSPs.
?DSPs on PVDM2 hardware are configured individually as either voice termination, conferencing, media termination, or transcoding, so that DSPs on a single PVDM may be used as different resource types. Allocate DSPs to voice termination first, then to other functionality as needed.
?The NM-HDV2 has 4 slots that will accept PVDM2 modules in any combination. The other network modules have fixed numbers of DSPs.
?A conference based on these DSPs allows a maximum of 8 participants. When a conference begins, all 8 positions are reserved at that time.
?The PVDM2-8 is listed as having ? a DSP because it has a DSP that has half the processing capacity of the PVDM2-16. For example, if the DSP on a PVDM2-8 is configured for G.711, it can provide (0.5 * 8) bridges/DSP = 4 conference bridges.
?Use Table 6-1 and Table 6-2 to determine how many DSPs may be provisioned with specific hardware.
?A DSP farm configuration in Cisco IOS specifies which codecs may be accepted for the farm. A DSP farm that is configured for conferencing and G.711 provides 8 conferences. When configured to accept both G.711 and G.729 calls, a single DSP provides 2 conferences because it is also reserving its resources for performing transcoding of streams.
?The I/O of an NM-HDV2 is limited to 400 streams, so ensure that the number of conference resources allocated does not cause this limit to be exceeded. If G.711 conferences are configured, then no more than 48 DSPs should be allocated per NM because (48 * 8) participants = 384 streams. If you configure all conferencing for both G.711 and G.729 codecs, then each DSP provides only 2 conferences of 8 participants each. In this case, it is possible to populate the NM fully and configure it with 16 DSPs so there would be 256 streams.
?Conferences cannot natively accept calls utilizing the GSM codec. A transcoder must be provided separately for these calls to participate in a conference.
?Any PVDM2-based hardware, such as the NM-HDV2, may be used simultaneously in a single chassis for voice termination but may not be used simultaneously for other media resource functionality. The DSPs based on PVDM-256K and PVDM2 have different DSP farm configurations, and only one may be configured in a router at a time.
http://www.cisco.com/en/US/partner/products/sw/voicesw/ps556/products_implementation_design_guide_chapter09186a00806e8c25.html
Mary Beth
