The SBC Core system contains the DSP firmware image called Universal XPAD (UPXPAD) which supports codecs within a single DSP firmware image.
UPXPAD
The UPXPAD utilizes external memory to:
- Support all codecs in a single DSP image. Codecs can be configured without system restart.
- Manage DSP channel counts based on resource utilization.
The UPXPAD allows operators to enable codecs and change codec/tone ratio mixes on SBC without impacting service while at the same time maximizing DSP channel capacity. Additionally, the single DSP compression image simplifies management of the DSP resources.
The DSP image also supports transcoding. This image uses external memory for storing channel data as well as code.
The main features of UPXPAD are:
- Single Image—All transcoding functions are in a single image and a single mode.
- Dynamic Resource Usage—Image supports the use of any mix of codecs on any channel up to maximum cycle budget. For example, the image supports up to 60 channels of G.726 codec or up to 24 channels of G.722.2, which are the budgeted maximum utilizing optimal cycle count for a DSP core. Image accepts any combinations of codecs until its cycle count is exhausted.
- DSP Channel Density—For some of the codecs such as G.726, G.723, G.722, the DSP image offers a better channel density. For complete DSP channel density details, see Appendix C, "DSP Channel Densities".
TNAPAD
The SBC supports TNAPAD as a separate image. TNAPAD generates call progress tones, plays announcement, and collects digits prior to call establishment.