Cisco Systems ICS-7750 manual DT-24+ and DE-30+ Digital Gateway Modules, DT-24+ Digital Gateways

Chapter 8 Features of Other Compatible Cisco Devices

DT-24+ and DE-30+ Digital Gateway Modules

DT-24+ and DE-30+ Digital Gateway Modules

The DT-24+ and DE-30+ digital gateways are modules that are used with Cisco CallManager to connect Cisco IP phones to the Internet. The DT-24+ or DE-30+ module is installed in a 32-bit Personal Computer Interface (PCI) slot in a PC desktop or server chassis.

Digital gateways differ from analog gateway products in that they support digital ISDN features including Direct Inward Dialing (DID) and caller ID. These features allow outside callers to dial directly to a particular user without going through an attendant (operator). In addition, digital interfaces usually provide a more economical interface choice when the number of trunks exceeds six to eight channels.

When more than one digital gateway is needed, the additional gateway can be treated as a separate gateway or aggregated with the other gateways as a common pool of channels. Any number of digital gateways can be installed in a network, and the number installed in a PC is limited only by the number of available slots.

Digital gateways communicate with Cisco CallManager, which allows the implementation of supplementary services such as holding, transferring, and forwarding of outside calls. Also, with proxy signaling provided by the Cisco CallManager, the digital gateways are fully compatible with H.323 V.2.

DT-24+ Digital Gateways

DT-24+ digital gateways provide the interface to the PSTN or existing PBX systems through T1 ISDN Primary Rate Interface (PRI) interfaces. DT-24+ digital gateways support up to 23 simultaneous channels of VoIP packet to circuit-switched adaption, G.711 encoding (A-law or mu-law), dual tone multifrequency (DTMF) detection, generation, and signaling, and line echo cancellation. Twenty-three simultaneous channels of G.723.1 encoding/decoding are also supported.

DT-30+ Digital Gateways

DT-30+ digital gateways provide the interface to the PSTN or existing PBX systems through E1 ISDN PRI interfaces. DE-30+ digital gateways support up to 30 simultaneous channels of VoIP packet to circuit-switched adaption, G.711

	Cisco ICS 7750 System Description
78-10360-02		8-5