Chapter 6 Configuring and Debugging Fax Services

Debugging the Cisco ATA 186/188 Fax Services

Step 3 At the DOS prompt of this directory, enter the following command:

:>rtpcatch <cap_file> [<prefix>] [options]

–<cap_file> is the NAI Sniffer capture file.

–<prefix> is the prefix prepended to the output filenames.

Output Files

The output files of rtpcatch include a summary file and audio stream files.

The summary file is <prefix>.sum if <prefix> is specified, otherwise it is file.sum.

Stream files are labeled with an integer tag beginning with 00. Stream files are also tagged with the extension pcm for G.711A/G.711µ-law, 723 for G723.1, 729 for G729, t38 for T.38, and cfr for Cisco Fax Relay.

Options

rtpcatch options include:

•-fax—to output the fax events for a connection.

The output includes "FAX summary 1" as the interleaved event list for all directions, and "FAX summary 2" as the event list for each direction. The reported events include voice codec change, NSE signalling, and fax relay events.

•-port <port0> <port1>—to discard any packets sent from/to this port.

If the NAI Sniffer capture file includes Cisco ATA prserv packets, these packets can interfere with rtpcatch analysis. Some prserv packets might be interpreted as NTE or NSE events. To prevent such interference, you can either disable debugging output on the Cisco ATA (do this by setting the Nprintf configuration parameter to 0), configure your NAI Sniffer to filter out the prserv packets, or run rtpcatch with the -port options.

Note rtpcatch works best for analyzing a single VoIP session. Command-line options can be entered in any order.

Example of rtpcatch

The section contains an example of using rtpcatch and includes an explanation of its output:

Output

C:\>rtpcatch faxpassthru -fax

 

 

 

[

25]open file: 00.723, (G723) 2.213:10000 =>

2.116:10002

[

26]open file: 01.723, (G723) 2.116:10002 =>

2.213:10000

[

29]

<00>

1

silence pkts from

TS 1760 (seq#

3)

[

42]

<00>

2

silence pkts from

TS 4400

(seq#

9)

[

47]

<00>

2

silence pkts from

TS 5600

(seq#

11)

[

55]

<00>

2

silence pkts from

TS 7760

(seq#

15)

[

101]open file: 02.pcm, (G711u)

2.116:10002 => 2.213:10000

[

106]

<02>

2

lost pkts from

seq# 39

 

 

[

107]open file: 03.pcm, (G711u)

2.213:10000 => 2.116:10002

[

110]

<03>

1

silence pkts from

TS 19440 (seq# 41)

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide for MGCP (version 3.0)

 

OL-4803-01

6-13

 

 

 

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Cisco Systems ATA 188, ATA 186 manual Example of rtpcatch, Output Files
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ATA 188, ATA 186 specifications

The Cisco Systems ATA 186, or Analog Telephone Adapter, revolutionized the way traditional telephony interacted with Voice over Internet Protocol (VoIP) systems. Designed primarily for home and small office use, the ATA 186 allows users to connect standard analog phones and fax machines to a network, enabling them to take advantage of the benefits of VoIP technology.

One of the defining features of the ATA 186 is its dual port architecture. It includes two FXS ports, allowing users to connect up to two analog telephones. This functionality means that multiple devices can leverage VoIP services simultaneously without the need for separate adapters for each phone. The flexibility of the ATA 186 helps streamline the user experience, facilitating voice communication over an IP network while ensuring users can still use their existing phone equipment.

The ATA 186 employs various technologies to maintain high-quality voice calls. It supports standard voice codecs such as G.711 and G.729, which ensure efficient bandwidth usage while preserving call clarity. The adaptive jitter buffer technology further enhances call quality, compensating for network variations and minimizing latency, which is crucial for clear and uninterrupted conversations.

Additionally, the ATA 186 provides users with advanced calling features that were traditionally available only on PBX systems. These features include caller ID, call waiting, and voicemail functionality, integrating seamlessly with typical telephony services. The device also supports T.38 fax relay, allowing users to send and receive faxes over the internet, thus addressing the needs of environments where fax communication remains essential.

The security of VoIP conversations is also a priority for the ATA 186. It employs encryption protocols such as Secure Real-time Transport Protocol (SRTP) and Transport Layer Security (TLS), ensuring that voice data is securely transmitted across the network. This focus on security helps protect sensitive information transmitted during calls.

Installation and configuration of the ATA 186 is streamlined, with an intuitive web-based interface that simplifies the setup process. This accessibility makes it suitable for users with varying levels of technical expertise, as frequently required adjustments, such as network configurations and firmware updates, can be easily managed.

In conclusion, the Cisco Systems ATA 186 stands out as a versatile and robust solution for users looking to integrate analog phones into a VoIP environment. With its dual port capabilities, high-quality voice codecs, advanced call features, and security measures, it offers a compelling choice for both residential and commercial users seeking seamless telephony integration. As technology evolves, devices like the ATA 186 remain cornerstones in bridging traditional telephony with modern communication systems.
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