Appendix D H.323 Signaling

H.323 Signaling Scenarios

Figure D-3 H.323 Call Setup from H.323 Network to Circuit Switched Network

 

 

Gatekeeper

Gateway to

Endpoint 1

CSN/PSTN

 

 

V

V

 

 

 

 

 

 

H.225 Admission Request (ARQ)

 

 

 

 

 

 

 

H.225 Admission Confirm (ACF)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Open TCP Channel for Q.931

 

 

 

 

 

 

 

 

Q.931 Call Setup

 

 

 

 

 

 

 

 

Q.931 Call Processing

 

 

 

 

 

 

 

 

 

 

H.225 Admission Request (ARQ)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H.225 Admission Confirm (ACF)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q.931 Alerting

 

 

 

 

 

 

 

Q.931 Connect

 

 

 

 

 

 

Open TCP Channel for H.245

 

 

 

 

 

 

H.245 Terminal Capabilites

 

 

 

 

 

 

 

H.245 Terminal Capabilites

 

 

 

 

 

 

H.245 Terminal Capabilites

 

 

 

 

 

 

H.245 Terminal Capabilites

 

 

 

 

 

 

Exchange of Master-slave Determination Messages

 

 

 

 

 

H.245 Open Audio Logical Channel

 

 

 

 

 

 

H.245 Open Audio Logical Channel Acknowledgement

 

 

 

 

 

H.245 Open Audio Logical Channel

 

 

 

 

 

H.245 Open Audio Logical Channel Acknowledgement

 

 

 

 

 

 

Bi-directional Audio with Transcoding Between Endpoint and Gateway

 

 

 

 

 

 

 

 

 

79600

 

Table D-5 Action Descriptions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Step

Action

 

Description

 

 

 

 

 

 

 

 

 

 

 

1.

Local Admission Request (ARQ)—Local

 

Cisco ATA sends a local ARQ message to the H.323 gatekeeper

 

 

endpoint to H.323 gatekeeper

 

seeking authorization to place a call over the H.323 network.

 

 

 

 

 

 

 

 

 

 

 

2.

Local Admission Confirm (ACF) or Admission

 

H.323 gatekeeper returns a ACF or ARJ message, indicating

 

 

Reject (ARJ)—H.323 gatekeeper to the local

 

whether or not the responding gatekeeper is going to allow the

 

 

endpoint

 

Cisco ATA device access to the network.

 

 

 

 

 

 

 

 

 

 

 

3.

Open TCP Channel for Q.931 messaging

 

TCP port 1720 is opened, making way for the forward and reverse

 

 

 

 

 

 

flow of Q.931 signaling messages between the H.323 endpoint

 

 

 

 

 

 

and the CSN/PSTN Gateway.

 

 

 

 

 

 

 

 

 

 

 

4.

Q.931 Call Setup—Local H.323 endpoint to

 

Call setup initiates from the local H.323 endpoint.

 

 

remote H.323 endpoint

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5.

Q.931 Call Proceeding—Remote H.323

 

Gateway acknowledges call setup initiation.

 

 

endpoint to local H.323 endpoint

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide (H.323)

 

 

 

 

 

 

 

 

 

OL-4008-01

 

 

 

 

 

 

 

 

D-15

 

 

 

 

 

 

 

 

 

 

 

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Image 193
Cisco Systems ATA 188 manual Action Description, Csn/Pstn
Page 192 Page 194

ATA 188 specifications

The Cisco Systems ATA 188 is a versatile Analog Telephone Adapter designed to facilitate the integration of traditional telephone systems with Voice over Internet Protocol (VoIP) networks. This device has been key in bridging the gap between legacy telephony and modern IP-based communication, allowing users to leverage their existing analog phones while enjoying the benefits of digital connectivity.

One of the main features of the ATA 188 is its ability to connect regular analog phones to a VoIP network, enabling users to make and receive calls over the internet. This significantly reduces calling costs, especially for long-distance and international calls. The ATA 188 supports two phone lines, allowing simultaneous voice calls. This dual-line capability makes it a suitable choice for small businesses or home offices that require multiple lines without the need for extensive infrastructure.

The device is equipped with various technologies that enhance its functionality. It supports the Session Initiation Protocol (SIP) and H.323, making it compatible with a wide range of VoIP service providers. Additionally, the ATA 188 features Quality of Service (QoS) settings, which prioritize voice traffic over the internet, ensuring clear voice quality without interruptions or delays. This is essential for maintaining a professional communication experience, especially in business environments.

Another characteristic of the ATA 188 is its user-friendly configuration interface. It allows users to easily set up and manage their devices through a web-based portal. The configuration process is straightforward, with options to adjust settings such as codec selection, call features including call waiting, and call forwarding functionalities.

Security is also a priority for the ATA 188, as it provides robust protocols to protect call data. The device supports Secure Real-time Transport Protocol (SRTP) and Transport Layer Security (TLS) to encrypt voice traffic and manage signaling securely. This ensures that sensitive conversations remain confidential.

Overall, the Cisco Systems ATA 188 is a reliable and efficient solution for users looking to transition from traditional telephony to VoIP. Its dual-line capacity, compatibility with multiple VoIP standards, user-friendly configuration, and built-in security features make it a valuable asset for both personal and professional communication solutions. In an ever-evolving telecommunications landscape, the ATA 188 remains a relevant and practical choice for integrating legacy telephony with modern internet-based services.
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