The 2-Wire networks typically carry voice, digits, fax, and modem traffic. Because the same twisted pair carries telephone signals in both directions, a frequent problem on these circuits is impedance mismatches that result in echo. Other impairments that may be present due to various transmission equipment include noise, low signal-to-noise, delay, attenuation, and distortion. Hence, a measure the quality of the signals over 2-Wire networks becomes essential for all service providers.

GL provides various solutions to capture calls on 2-wire lines. A voice call can be captured for call and digit analysis. A fax call between two fax machines can be captured and analyzed for fax image, protocol, data rate, and page errors. A modem call between two modems can be captured and analyzed for modem phase changes, retrains, rate renegotiations, data rates, and symbol rates. Not all modem calls can be analyzed completely.

A brief list of 2-Wire Traffic Capture & Analysis solutions is given below.

Voice /Data Capture

• Using Voice Recorder software with Dual UTA HD

  Voice Recorder Software with GL’s Dual UTA HD (High Density) offers a solution to capture 2-Wire Voice, Fax, and Modem traffic. Using the 2-wire Phone Tap adaptor, one can non-intrusively ‘tap’ into the analog 2-wire line via the RJ11 interface and capture the bi-directional voice. The recorded PCM voice/data files can be analyzed using GL Insight™ Modem and Fax Analysis Software and/or Adobe Audition software (optional 3rd party software) for 2-wire Analog interface.

• Using Call Capture & Analysis software with USB T1/E1 Analyzer

  The Call Capture & Analysis (CCA) application in T1/E1 Analyzer provides the capability to non-intrusively record calls directly from T1/E1 lines. The captured files can be analyzed using GL Insight™ Modem and Fax Analysis Software for 2-wire Analog interface. Automatic call capturing can be triggered from both directions (east and west) of transmission wherein all 24 or 30 channels are scanned for call initiation and recording. The trigger types for capturing traffic includes signaling based triggers - CAS -R1, wink start, MFC-R2, ISDN/SS7 messages , and traffic activated triggers based on Voice, Tones, Fax, and Modem.

• Using VQuad™ with FXO option

  GL provides the solution for testing WB analog 2-wire interfaces using GL's VQuad™ with Dual UTA HD hardware. The hardware connects to any PSTN, ATA, and next generation Gateways  supporting Wide Band (WB) and Narrow Band (NB) HD and SD Audio. This includes dual analog 2-wire interfaces (RJ-11) and, when coupled with the GL VQT, provides the necessary voice quality measurement and analysis tools. The VQuad™ with Dual UTA HD also adds the functionality for Round Trip Delay and One Way Delay measurements. The Dual UTA HD also support Echo measurements, multiple tone detection (including busy, fast busy, SIT), Caller ID detection and display, and Flash Hook. The Dual UTA HD FXO is fully user configurable and allows most any type of connection and multiple stage dialing (including immediate connect for PBX systems).

• Using MAPS™ APS

  MAPS™ APS (Analog Phone Simulator) is the high capacity Analog 2-wire Bulk Call Generator used to test a Central Office (CO), PBX, ATAs, Gateway or other telecommunications equipment, which provide local loop interfaces. MAPS™ APS system supports up to 96 independent FXO ports per 1U MAPS™ APS Server and an APSCB-48 unit. More can be achieved with a 4U MAPS™ APS Server sporting 2 Octal T1E1 Cards to support up to 384 analog ports. It includes a compact system comprising of MAPS™ APS, Analog Interfaces, Patch Panels and other optional modules (Fax Emulation and VQT Analysis) in a rackmount system.

Voice /Data Analysis & Decode

• Using Adobe Audition for Voice File Analysis

  Adobe Audition is an auxiliary (shareware) program that can be used to view, record, and listen to audio signals on 2-Wire, and T1 or E1 lines in real-time as the signals occur. Other features of the program include viewing of A-law and u-law encoded voice and many other encodings, viewing of two files side by side for comparison purposes, accurate measurement of timing information, and spectral displays.

• Using GL Insight™ for Fax and Modem Analysis & Decode

  GL Insight enables decoding and analyzing pre-recorded modem and fax transmissions. The transmission signals are recorded over PSTN and IP media. GL Insight™ uses recorded PSTN files or IP data streams and demodulates them. It then analyzes the results to detect the problem and report where it lies. The results of the analysis can be viewed in user-friendly textual and graphical formats.

• Using VQuad™ for PDD and PRD measurements

  Post Dial Delay (PDD) & Post Ringback Delay (PRD) measurements analysis functions require the use of GL's 2-wire phone tap along with GL's VQuad™ software. The PDD is the measurement between the trailing edge of the last DTMF digit sent and leading edge of the Ringback tone coming from the far end switch. The PRD measurement detects from the end of the Ringback to the beginning of the call.

• Using Voice Band Analyzer for complete voice-band analysis

  Voice-band Analyzer (VBA) is an analysis tool for monitoring voice band traffic over VoIP, TDM, 2-Wire, and Wireless networks. The VBA application operates on previously captured files. Built-in algorithms include ITU-T P.56 Active Voice Level analysis, and Line Echo (Hybrid) analysis. Other analysis modules such as ITU-T P.561, P.562, and P.563 can be hosted as plug-ins.