Call Capture and Analysis

The Call Capture and Analysis (CCA) application is used to capture calls directly from the T1, E1, and 2-Wire lines.

The application uses GL's T1 E1 Analyzer Hardware Units to interface non-intrusively with T1 or E1 lines.

The Call Capture & Analysis (CCA) application is used to initiate recording of calls, either automatically or manually on both East and West directions simultaneously. The auto scanning provides traffic and signaling based triggers. Signaling triggers supports call capture based on ISDN, SS7, CAS (R1, wink start, MFC-R2) messages. The traffic activated triggers supports call capture based on voice, fax, modem, tones, & any traffic with specified power level.

Subsequently, play back the captured calls using a third party audio editing software tools (Adobe Audition/Goldwave) and analyze in time and spectral modes.

When used in conjunction with Voice Band Analyzer and Call Data Records, the captured signaling and voice can be used to trouble-shoot customer complaints of voice call quality, voiceband data, fax quality, and tones and dual tone transmission issues.

Automatic call capturing can be triggered from both directions (east and west) of transmission.

The call capture application supports following types of triggers for auto capturing of call

• Signaling based triggers - CAS -R1, wink start, MFC-R2
• ISDN and SS7 message based triggers
• Traffic activated triggers
• Voice based on a minimum power level
• Tones of specified frequency - Ring back tone, Dial tone, Busy tone, and DTMF digits
• Fax traffic - V.32 / V.17, V.27, V.29,
• Modem traffic - V.22 forward/reverse channel, V.34 & V.90 uplink, Binary V.90 downlink, FSK
• Any type of signal based on any power level
• Supported codecs data rates are - a-law, µ-law, 16-bit PCM (Intel), 16-bit PCM (Motorola), MS Wave, G.726 (40 Kbps, 32 Kbps, 24 Kbps, and 16 Kbps), and 14-bit 16 KHz G.722 (64 kbps)

Subsequently, captured calls can be played back and analyzed in time and spectral modes using a commercial sound card, built-in high fidelity speakers, and audio viewing software (Adobe Audition, Goldwave).

Frequency, power of east and west directions cannot be shown in real time in CCA application. We can only capture the files. The application also indicates the channels on which a recording is taking place and the files names to which data is being stored. Scanning mode is possible wherein all 24 or 30 channels are scanned for call initiation and recording. A message area provides status of the capture process. Other features include,

Operating Modes	Ability to capture calls using either Manual Capture mode or Auto Scanning mode. Automatic or Manual termination of recording. Each capture instance is identified by a unique probe name, and can have different capture options, such as the timeslot selection, output directory, recording time, and so on
Encoding Formats	Supported codecs data rates are - a-law, µ-law, 16-bit PCM (Intel), 16-bit PCM (Motorola), MS Wave, G.726 (40 Kbps, 32 Kbps, 24 Kbps, and 16 Kbps), and 14-bit 16 KHz  G.722 (64 kbps) Automatic conversion of u-law and a-law PCM files to WAV file format if required.
Captured Results	All call data are captured including signaling bits, voiceband data, signaling protocol data (e.g. DTMF or MF digits), and various types of traffic such as fax, modem, & voice Captured PCM data is saved as two synchronized disk files (east and west directions) for post processing. A separate signaling file for E1 and T1 is created. Supports logging of call summary records, facility alarms, and supervisory signals in CSV or binary file formats. Results from CCA include - voice capture for both directions complete signaling information for each direction for CAS, ISDN, MFC-R2, and SS7 all alarms and errors occurring during the call including BPV, Frame Errors, CRC errors, LOS, and more Time, spectral, and spectrogram mode views of recorded data using View PCM or Adobe Audition.
Captured File Name Handling	Various ‘File Naming’ conventions based on the type of capture. The file naming conventions suit various types of capture applications such as MFC-R2, signaling, ISDN capture, manual capture etc. Provides an option of stamping the captured files sequentially or with date/time. The digit-parsing feature of CCA application helps user to distinguish CAS-R1 or MFC-R2 calls by prefixing called or calling numbers to the filename.
Trigger based Capture	Capture modes can be triggered from both directions (east and west) of transmission simultaneously. Ability to capture on a single direction also (East or West side) Supports following trigger activations – Signaling (CAS -R1, wink start, MFC-R2), Message based (ISDN, SS7) Traffic based (voice, fax, modem, tones, digits…)
Filters	‘Call filtering’ feature is used to capture calls with a user-defined called and calling numbers rather than all calls
Auto Signaling Trigger Options	Requires user-defined start and stop ABCD signaling bits , user-defined mono or dual tones , or a combination of user-defined start and stop signaling bits followed by a user-defined mono or dual tone to initiate and terminate capturing of calls on chosen timeslots
Auto ISDN Trigger & Capture Options	Supports capturing ISDN calls with or without NFAS options ISDN calls are recorded with CRV, ISDN message type, channel, direction, called and calling numbers. ISDN calls can be captured with customized called and calling number filter.
Auto SS7 Trigger & Capture Options	Detect and capture SS7 calls by defining DPC, OPC, and CIC groups. SS7 calls can also be captured with customized called or calling number filter. CCA also allows to capture SS7 calls on multiple T1 E1 trunks using a signaling link that may be on a different physical trunk than the telephony circuits.
Auto Traffic Activated Capture	Trigger capture based on various kinds of traffic such as fax, modem, tones of standard frequency, digits, and voice. Users can also define the traffic algorithms such as linear, quadratic, hybrid, or hybrid filtered that performs the traffic classification.

Automatic Call triggering can be done in one of the following ways:

• A, B, C, D - Signaling Bits- with user-defined start and stop ABCD signaling bits to initiate and terminate recording of files on chosen timeslots - useful for CAS calls. In addition, CAS signaling such as DTMF digits, MF digits, and MFC-R2 digits conveying "called and calling numbers" are decoded and attached as part of the captured file name.
• Tone - user-defined mono or dual tones can trigger the capturing of a call CCA - useful for fax calls
• Signaling + Tone - a combination of user-defined Start/Stop signaling bits followed by a mono or dual tone (user-defined) within a specified timeout period - useful for capturing fax calls
• ISDN calls - capture gets triggered when any ISDN calls are placed. Called and calling number can be gathered as part of the capture process and attached to the captured file name. During call capture, the following parameters are displayed: ISDN message types, CRV, Time slot, card number, called and calling numbers.
• SS7 calls - SS7 voice calls are kept in CIC groups. When an SS7 call is detected, an Origination Point Code (OPC), a Destination Point Code (DPC), and a CIC # is retrieved. If the comparison holds good capture task is performed, otherwise the call is discarded.
• Traffic activated - With this trigger option, it is possible to trigger on various kinds of traffic such as fax, modem, tones of standard frequency, digits, voice, and any signal based on power level. Users can also define the traffic algorithms such as linear, quadratic, hybrid, or hybrid filtered that performs the traffic classification.
  

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Multiple Call Capture and Analysis

GL’s Multi CCA application is similar to CCA, where in it is used to monitor hundreds of calls, capture the bidirectional data, signaling and traffic, simultaneously from multiple T1/E1 lines, based on the user-defined trigger configurations. Once the capture trigger type is selected, users can control and run multiple capture instances on different T1/E1 ports from a single GUI.

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Applications of CCA

• Call recording for post analysis
• Analysis of single/dual tones, DTMF and MF digit analysis (frequency, power, duration)
• Analysis of call quality (speech levels, noise levels, echo return loss, speech clipping, impulse noise, and other impairments)
• Call activity, call density, and call volume analysis
• Monitoring and recording Fax, Voice Modem, ISDN, SS7 and CAS calls
• Filtering of calls by "called" and "calling" number
• Listening to finished calls and active calls as they are occurring
• Remote monitoring of calls including remotely listening to calls

  GL also provides other various transmission & capture software that helps is call monitoring & analysis over network. Visit Call Signaling and Analysis page for more details.

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Operating Modes & other Call Capture Options

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Call Playback and Viewing Features

Oscilloscope (Time Series) View

For a recorded call, a graph of the amplitude vs. time can be displayed. The display can be for either one side or both sides of the call. Playback, zoom-in, zoom-out, and other options are available for analysis of partial and/or full call data/ Signaling data during call set-up can be analyzed e.g. DTMF/MF, dial and busy tones at microsecond duration granularity. Every sample is recorded and displayed.

There are several methods for viewing captured files supported by various visualization programs such as Adobe Audition and Goldwave programs. Adobe Audition and Goldwave are used with a variety of file formats including PCM, wav, and others. Refer to Adobe Audition and Goldwave User's Guide for detailed instructions or Contact GL Communications Inc for additional details or clarifications about this.

Spectral View

A graph of power level vs. frequency is displayed for the user-selected portion of the recorded call. Users can set the frequency resolution and frequency band of interest. The display can be either one side or both sides of the call. Useful for DTMF/MF, dial, busy tone, speech and modem frequency analysis. Spectrogram displays are also possible.

Goldwave/Adobe Audition

The wave graph of captured files can be visualized using 3rd party audio editing software such as Goldwave or Adobe Audition. The graphical software program should be installed in order to directly invoke captured files through GL's T1E1 analyzer. Goldwave can be used to visualize maximum of two files.

To view stereo wave graph select dual files to view both the graphs simultaneously.

The names of the files chosen for display is merged as one *.wav file. Goldwave uses variety of file formats including *.pcm, A-Law, Mu-Law, *.wav, and others. Any file formats chosen is converted to *.wav while displaying graphs.

Example: For dual file graph display, select "Samp_wst.pcm" and "Samp_est.pcm", a single "Samp_wst_ Samp_est.wav" file is created and the graph is displayed one below the other.

Tabular Analysis

A special DOS application is provided for MFC-R2 digit analysis (r2ana.exe). With this software captured files can be analyzed for R2 tones and signaling. Forward and backward-paired tones are detected and displayed with time stamped indications of digit durations and signaling changes. Call duration, timeslot, date, and time of occurrence are also recorded.

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ISDN Call Capture Options with NFAS (Non-Facility Associated Signaling)

CCA is capable of capturing ISDN calls with or without NFAS option. For calls with NFAS, one needs to identify the NFAS interface options (Explicit / Implicit) using the ISDN Analyzer.

The CCA gets triggered when any ISDN calls are placed. Capture occurs after the ISDN message, "SETUP", is detected with the called/calling number that matches the filtering definition for ISDN Call Filtering Options.

CCA can be set to capture the ISDN calls on the trunks that contain D-Channel using options under NFAS. NFAS is a standard option available for ISDN PRI call processing system. This allows a single D channel to control multiple PRI trunks. With NFAS option, a single D-channel can control a maximum of 479 B-channels, i.e., up to 20 trunks (or a maximum of 478 with one B-channel as a backup). In case of GL's Dual T1/E1 Analyzer, a maximum of 95 B-Channels, i.e., up to 4 trunks is supported.

• NFAS D-Channel -  Allows to capture ISDN calls with the NFAS signaling
• D-Chan # - Used to specify the T1/E1 trunk that contains the D-Channel or signaling
• Explicit Interface -  With this, the CCA is set to capture NFAS calls for the trunks which does not include D-Channel, i.e the calls over NFAS group members. Each group member is identified based on the Explicit interface identifier. All messages are “explicitly defined” with an “interface identifier” of 0,1,2,3,4,5,6,7 depending on which bearer has the traffic
• Implicit Interface -  With this, the CCA is set to capture the calls on the trunks containing D-Channel

For more information, refer to ISDN Analyzer.

User will be able to determine the Explicit Interface number based on “Interface Identifier Present” and “Interface Identifier” parameters in ISDN SETUP message as captured in ISDN Analyzer. If the ISDN call is explicit then configure CCA as per the Explicit Interface Number observed in the analyzer.

In NFAS, The trunk which contains the D-Channel can be of Explicit or Implicit interface. If it is an Explicit Interface, normally its Explicit Interface number will be ‘0’. If it is an Implicit Interface, then it does not contain any Explicit Interface number.

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SS7 Call Capture Options

SS7 voice calls are kept in CIC groups. When an SS7 call is detected, an Origination Point Code (OPC), a Destination Point Code (DPC), and a CIC # is retrieved. If the comparison holds good capture task is performed, otherwise the call is discarded.

Configure Redundant Data Links

• Data Rate: The possible data rates are 56 or 64 kbps. The SS7 facility data link is a clear channel circuit dedicated to the transmission of SS7 messages. The data rate of this link is commonly 56kbps in ANSI networks and 64 kbps in ITU and other networks. Signaling data links are assigned to an E1/T1 (DS0) timeslot. Not supported is the T1 variant where an entire T1 span is used for signaling.
• Call Filtering:  SS7 Call Filtering allows users to search the SS7 call setup Initial Address Message (IAM) to a specific called or calling number. SS7 Call Filtering is similar in functionality to that used in ISDN filtering. Regular expressions such as "*", and "?" can be used. An expression such as "123*" means only call #'s that start with "123" have a possibility of being captured. 
• Signaling Links:  Signaling links are usually assigned in pairs for redundancy and may or may not be contained in the voice trunks. Links are engineered to carry 40% of the expected load so if a redundant link fails the load would be 80% of capacity. Depending on their locations in the network, links have designations as either A (access), B (bridge), C (cross), D (diagonal), E (extended), or F (fully associated) links. It will take two trunks (cards) to monitor each data link or four trunks (cards) to monitor two data links. CCA allows two sources of signaling to be used, primary and secondary. Each direction of the link is designated as Uplink and Downlink. The port selection for uplink and downlink must be on the same card. Incoming calls are detected on the signaling timeslot. A signaling timeslot cannot also be used for voice data.
  
  
  • First Card # - Designates the signaling trunk and timeslot used for a primary link. When monitoring a single link designate the connect card (ports) and the timeslot that contains the signaling.
  • Second Card # - Designates the signaling trunk and timeslot used for a secondary or redundant link.
    
    
• Protocol selection - used to select the appropriate protocol standard being used on the signaling link, such as, ITU, ANSI, ETSI, and China variants are selectable.
• Circuit Group (CIC) Configuration – Bearer traffic is connected between two exchanges with call setup messaging using relative Originating Point Code (OPC) and Destination Point Code (DPC) along with associated Circuit Identifier Codes (ITU 1-4096, ANSI 1-16384) entered with Port Identifications (Card X and Card Y) identifying the signaling trunk and timeslot.

• Device Selection – designates the bearer trunk to be monitored as West and East direction trunks.
• CIC Start – CIC Quantity – Timeslot Start - Timeslots and CICs are generally sequential, although sometimes the timeslot 16 may be skipped e.g. when timeslot 16 is used for framing.  
  Starting TS identifies where the assignment starts as in some cases a timeslot may be allocated to carry the signaling link. CIC Quantity specifies the number of CICs to assign.
• Skip Options - In the E1 protocol, channel 16 is typically used as a signaling channel.  CCA now provides the option to map the CICs to the timeslots by either skipping timeslot 16 so it can be used for signaling, or NOT skip channel 16 and map the timeslot to a CIC number. The following options are available regarding skipping:
  
  Both TS 16 and CIC are checked – in this case TS 16 is not used for bearer traffic, and CIC numbering also skips. This means that if TS 15 had CIC as “X”, then TS 17 would have a CIC as “X+2”
  Only TS 16 is checked – in this case TS 16 is not used for bearer traffic, but CIC numbering is still consecutive. This means that if TS 15 had CIC as “X”, then TS 17 would have CIC as “X+1”
  Nothing is checked – in this case CIC numbering is consecutive

The information below displays examples of how the CIC numbers are mapped to the channel numbers for with and without ‘Skip Timeslot 16’ selections.

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Traffic Triggered Call Capture

CCA also includes a feature to trigger capturing of calls based on various types of traffic such as fax, modem, voice, standard tones, digits, and so on. They are V.22 bis forward channel, V.22 bis reverse channel, V.34 & V.90 uplink, V.29, V.32/V.17 > 2400 bps, V.27 ter @ 4800 bps, V.27 ter @ 2400 bps, Voice, binary V.90 downlink, FSK, DTMF digits, Dial tone, Ringback, and Busy tone. Detecting the above types of traffic requires use of the traffic classifier.

A 2048 byte (256 ms) block of data is sent to the traffic classifier. The traffic classifier determines if the data is one of the accepted types of traffic. If the condition is met, then capture of the traffic data commences.

Unlike the other traffic options, triggering on voice traffic can be fine-tuned to the power level of the voice data. Setting the voice power level can be used to filter out weak or undesirable voice data.

Note: CCA requires additional license for traffic activated triggering (XX031).

There is also an option "Any Signal" to be defined in dBm. Selecting this feature bypasses the traffic classifier and detects the power level of the data. If it exceeds the defined input data (e.g. -10dBm), then capture commences.

Stopping Traffic or "Any Signal" Capture

Setting the "Silence Options" slider allows for hang-ups during the capture of traffic or "Any Signal" data. For example, if DTMF traffic is being captured, and then non DTMF data is detected, capture continues until the hang-up time limit set by "Silence Options" is exceeded. If the data reverts back to DTMF, the capture continues as it was before the hang-up.

If the hang-up time limit is 400 milliseconds, only one hang-up is allowed before capture is terminated. Each buffer of data is of size 2048 bytes (256 ms).

Traffic Algorithm

The traffic classifier uses four different algorithms to choose from: Linear, Quadratic, Hybrid, or Hybrid Filtered.

• Linear - This algorithm is quicker to computer
• Quadratic - This gives better accuracy but need more time
• Hybrid (Recommended) - It is a combination of linear and quadratic, and the most reliable
• Hybrid Filtered - This eliminates misclassifications, for example, voice with many periods of silence.

The "Hybrid" is recommended algorithm and is used by default in the Multiple Call Capture.

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Digits, Tones, Signaling Triggered Call Capture

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Call capture using WCS

GL's Windows Client/Server makes the T1/E1 Analyzer as server and allows performing of typical tasks such as real time recording and transmission to/from files, dtmf/mf/mfcr2 digit detection and generation, bit error rate testing, alarm monitoring, Digital Signal Processing (DSP) operations, DS0 power monitoring, and protocol decoding from multiple client locations.

GL's CAS simulator is a client-side application that works along with the GL's T1/E1 Analyzer. It can simulate and analyze any user user-defined CAS protocols by providing signaling bit transitions and forward/backward frequency tones/digits. In addition to generating/receiving CAS calls, the CAS simulator also processes the receipt of Dialed Number Identification Service (DNIS) and Automatic Number Identification (ANI) information. Supported protocols include E1 MFCR2, T1 Winkstart, T1 Loopstart and Groundstart, E1 European Digital CAS, and any User-defined CAS.

Visit following webpages for more information

• Client Server for T1/E1 Analysis Cards
• Scripted DSP Capability
• Channel Associated Signaling Simulator

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CCA with other GL applications

Call Data Record (CDR)

• The application works with CCA (Call Capture and Analysis) and VBA (Voice Band Analyzer) applications and generates Call Summary and Call Detail reports. CDR provides comprehensive information on each and every call occurring on T1 E1 lines, including voice capture, signaling information for CAS, ISDN, MFC-R2, SS7, all alarms and errors occurring during the call, detailed voiceband event information (dual tones, fax tones, modem signals, and more), detailed analysis of the voiceband call including noise level, speech level, speech activity factor, echo measurements, and more. It also categorizes call as voice, fax, modem, or data.

Near Real-Time Voice Band Analyzer

• The Near Real-time Voice-band Analyzer (VBA) is an analysis tool for monitoring voice band network traffic. The VBA can host different analysis modules for monitoring speech and noise levels, line echo. VBA operates in near-real-time, processing the signal files recorded by CCA. VBA records its output into two files, the first containing overall channel measurements, and the second containing event records.

GLInsight™

• The captured files containing fax and modem information can be analyzed using GL Insight™ Modem and Fax Analysis Software for 2-wire Analog interface.

FaxScan™

• The captured files containing fax and modem information can be analyzed using FaxScan™ application to provide analysis of the T.38 packets, T.30 frames, decode a Fax TIF image, and general call-flow indicators for detail analysis.

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Additional Sample Screens:

• Call Capture Analysis Main Menu
• Call Capture Analysis Configuration Tab
• Call Capture Analysis Timeslots Tab
• Call Capture Analysis ISDN Options Tab
• Call Capture Analysis SS7 Option Tab
• Call Capture Analysis User Defined Tab
• Call Capture Analysis Tone Detection Parameters Tab
• Call Capture Analysis Traffic Options Tab
• Call Capture Call Storage Options Tab



Call View Screens

• Time Series Display
• Spectrum Display

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Bridge and Monitor Connections

• Monitor from a DSX-Patch Panel
  
• Bridge Mode Connections for Monitoring T1/E1 Signals for RJ-45
  
• Bridge Mode Connections Alternative Method
  
• RJ-45 Connections

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Resources

Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on.Therefore, XX can either be HDT, HDE, HUT, HUE, UTA or UEA depending upon the hardware.