Step

Appendix D H.323 Signaling

H.323 Signaling Scenarios

Table D-5 Action Descriptions (continued)

Step	Action		Description

6.	Gateway Admission Request		(Somewhat simultaneous, chronologically, to call setup and call
	(ARQ)—SCN/PSTN Gateway to H.323		proceeding) Gateway contacts the common H.323 gatekeeper,
	gatekeeper		seeking authorization to complete the two-way H.323
			network-to-CSN/PSTN Gateway call.

7.	Gateway Admission Confirm (ACF) or		H.323 gatekeeper returns a ACF or ARJ message, indicating
	Admission Reject (ARJ)—H.323 gatekeeper to		whether or not the responding gatekeeper is going to allow the
	CSN/PSTN Gateway		Gateway access to the network.

8.	Q.931	Alerting—Gateway endpoint to local	Status message is sent to calling H.323 endpoint advising that the
	H.323 endpoint		called party has been notified (phone ringing).

9.	Q.931	Connect—Gateway to local H.323	Status message is sent to calling H.323 endpoint advising that the
	endpoint		called party has answered the call (phone off hook).

10.	Open TCP Channel for H.245		Dynamically assigned TCP port is opened on both the local H.323
			endpoint and the Gateway, allowing for subsequent call setup
			activities (transmission and reception capability exchange,
			master-slave relationship determination, and so on).

11.	H.245	Terminal Capabilities	Various endpoint transmission and reception capabilities defining
			operation of voice, video, and data are exchanged and
12.	H.245	Terminal Capabilities	operation of voice, video, and data are exchanged and
12.	H.245	Terminal Capabilities	acknowledged to ensure consistent, reliable two-way

13.	H.245	Terminal Capabilities
13.	H.245	Terminal Capabilities	communication between the H.323 endpoint and the Gateway.
			communication between the H.323 endpoint and the Gateway.
14.	H.245	Terminal Capabilities

15.	Exchange of Master-Slave Determination		Determines master and slave assignments between the H.323
	Messages—Remote H.323 endpoint to local		endpoint and the Gateway.
	H.323 endpoint

16.	H.245	Open Audio Logical Channel—Local	Before actual transmission or reception of voice, video, or data,
	H.323 endpoint to remote H.323 endpoint		notification that the primary logical channel for the local H.323
			endpoint has been opened, ensuring clear two-way
			communication.

17.	H.245	Open Audio Logical Channel	Gateway acknowledges readiness.
	Acknowledgement—Remote H.323 endpoint to
	local H.323 endpoint

18.	H.245	Open Audio Logical Channel—Remote	Before actual transmission or reception of voice, video, or data,
	H.323 endpoint to local H.323 endpoint		notification that the primary logical channel for the Gateway has
			been opened, ensuring clear two-way communication.

19.	H.245	Open Audio Logical Channel	Local H.323 endpoint acknowledges readiness.
	Acknowledgement—Local H.323 endpoint to
	remote H.323 endpoint

20.	Bi-Directional Audio with Transcoding Between		Two-way communication ensues between the local H.323
	Endpoint and Gateway		endpoint and the CSN/PSTN Gateway.

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

	D-16	OL-4008-01

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.

Description

OL-4008-01

ATA 188 specifications