Specifications

Typical Configurations
51
CX Hardware Configurations
In addition to the two devices installed on the main board, DSP resources may be added to a
CX system using the Dual DSP Module (2 devices), the Quad DSP Module (4 devices), or the
T1/E1 Combo Module (1 device). The Combo module also adds a 32-channel hardware echo
canceller.
On system start-up, the system assigns the various DSP resources configured on the system
as illustrated in Table 20 above. There are 3 types of DSP loads: Echo Cancellation, Telephony,
and Compression. All loads are mutually exclusive and cannot be loaded on the same DSP.
• DSP Echo resource. An “E” indicates that the DSP is being allocated as an echo resource.
On system start-up, one DSP is allocated as an echo resource in all configuration. The
DSP echo resource provides 12 channels of echo cancellation. The system software uses
the DSP echo resources first and overflows to the VEC resource on the T1/E1 Combo card
if available. Allocating DSP echo resources first provides the system with consistent echo
quality with or without the addition of hardware echo cancellation.
• Telephony resource. A “T” indicates that the DSP is being allocated as a telephony re-
source. A telephony resource supports the following features:
- Tone generation
- Tone detection
- Voice mail (can be configured up to the maximum shown in the table; 10x3 is 30
channels, which could be up to 5 6-party conferences or any other combination. The
maximum conference size is 8 parties.)
- Record-a-call (The number of voice mail conferences includes record-a-call. If you
have 10 conferences and 16 voice mail, you could actually have access to 6
conferences and 12 voice mail and the other 4 could be used for record-a-call).
• G.729a Compression resource. The “C” indicates that the DSP is being allocated as a
G.729a compression resource (if a compression license was purchased). Each DSP com-
pression resource can support up to 8 simultaneous G.729a compression sessions.
Refer to Table 20 and Table 21 below to determine the maximum feature availability for various
hardware configurations of the CX.