# NMS DLCP system overview

To develop DLCP applications, you must have the following hardware and software:

- One or more CG 6000, CG 6000C, CG 6100C, or CG 6500C boards

- Natural Access

- NMS DLCP software (installed when you install Natural Access)

- Aztek Access303, Exchange303 (GR303) or AV5 (V5.2) protocol stack software

- C/C++ development environment

DLCP (GR303 or V5) systems are based on several components. CG boards provide a physical layer hardware platform. The DLCP software provides GR303 and V5.2 protocol-specific interfaces so that NMS hardware can support protocol Layer 1 functionality. Applications also use Aztek's Access303, Exchange303, or AV5 protocol stack software to integrate GR303 or V5.2 compliant upper layer interfaces. The following illustration provides an overview of the NMS DLCP system environment:

To perform CG board switching, media processing, or signaling processing tasks, applications can invoke functions from Natural Access. For example, GR303 and V5 protocols require dynamic switching between timeslots on a per-call basis. Applications can do this by using functions from the Switching (SWI) service. In addition, the GR303 protocol defines a 16-state robbed-bit signaling option for transmitting call-processing messages between the RDT and the IDT. Applications must use the ADI service to control CAS robbed-bit signaling required by the GR303 protocol.

The application may also need other NMS software, such as ISDN protocol software to terminate ISDN calls, or NMS Fusion software to implement VoIP gateway functionality. The system can also use additional NMS boards to perform as ISDN PRI or BRI line cards.