1. Slide 1Copyright : Valiant Communications Limited - 2007 VCL-EC TM T1 Echo Canceller (Upto 10 Echo Canceller per Chassis) V aliant C ommunications L imited Telecom Transmission Solutions Updated : March, 2007 U.K. Valiant Communications (UK) Ltd 1, Acton Hill Mews, 310-328 Uxbridge Road, London W3 9QN, United Kingdom E-mail: gb@valiantcom.com Website: http://www.valiantcom.com INDIA Valiant Communications Limited 71/1, Shivaji Marg, New Delhi - 110015, India Phone: +91-11 4105 5601, 91-11 4105 5602 Fax: +91-11 4105 5604, 91-11 2543 4300 E-mail: getinfo@valiantcom.com Website: http://www.valiantcom.com U.S.A. Valcomm Technologies Inc. 4000 Ponce de Leon, Suite 470 Coral Gables, FL 33146 United States of America E-mail: us@valiantcom.com Website: http://www.valiantcom.com

2. Slide 2Copyright : Valiant Communications Limited - 2007 Product Overview Robust and cost effective E1 and T1 echo canceller and voice quality enhancement solutions for the long distance, wireline, wireless, (GSM, CDMA), VoIP, satellite and radio communications The VCL-EC, T1 echo canceller are offered to provide cancellation of 64ms/128ms (user selectable) echo tails The echo canceller equipment is compliant to ITU-T G.164, G.165, G.168 (2000/2002) requirements for echo cancellation The echo canceller supports fax/modem G.164 and G.165 (2100 Hz) tone disable function The echo canceller is equipped to offer redundant power supply (optional) The equipment offers RS232 serial interface for configuration through a PC COM Port, and an Ethernet (10BaseT) interface for remote LAN configuration and monitoring which allows the user to monitor and configure the equipment over a TCP-IP network from anywhere in the world T1 Voice Echo Canceller - 3U (10 per Chassis)

3. Slide 3Copyright : Valiant Communications Limited - 2007 Product Overview The echo canceller solutions offers carrier-grade voice quality per AT&T Voice Quality Assessment Lab The echo canceller equipment offers fault recovery feature. It offers automatic by-pass upon power-supply failure/removal power supply. (i.e. it offers T1 circuit by-pass in the event of power supply failure) T1 echo canceller signaling protocols supported: –24B (24 Voice Channels) with out-of-band signaling –C7/SS7 Signaling on any user selected time-slot –23B+D,PRI ISDN (23 Voice Channels+D Signaling Channel) –Robbed Bit Signaling –All signaling options are User Selectable/User Configurable T1 Voice Echo Canceller - 3U (10 per Chassis) Types of Echo canceller offered User Selectable: 128ms - Unidirectional (cancels the echo with upto 128ms tail at the far end). 64ms - Bidirectional (cancels the echo with upto 64ms tail in both directions).

4. Slide 4Copyright : Valiant Communications Limited - 2007 Applications Datacomm Applications: Voice Over Frame Relay, Voice Over ATM, Voice Over Internet/LAN (VoIP). Central Office and PBX Applications: Network Trunks, Echo Canceller Pool, Common Equipment, Audio Conferencing Bridges. Voice Over ATM Applications: A multi-channel echo canceller resource or pool is shared among many channels to reduce cost, Echo cancellation is done at a DS0 level. Satellite Communications Applications: Digital Circuit Multiplication Equipment (DCME). Wireless Applications: Digital Cordless and Cellular Basestations, GSM, CDMA, Access Controllers. Voice Over Frame Relay, ATM Applications: Frame Relay and ATM routers and switches introduce large, variable, and unpredictable delays, Echoes from the Public Switched Telephone Network (PSTN) in combination with the delays from Frame Relay and ATM. Equipment yield objectionable speech quality. T1 Voice Echo Canceller - 3U (10 per Chassis)

5. Slide 5Copyright : Valiant Communications Limited - 2007 Features & Highlights T1 Voice Echo Canceller - 3U (10 per Chassis) 64 ms/128 ms echo cancellation confirms to ITU-T G.165 and G.168 ITU-T G.164/G.165 Disable Tone detection supported on all audio paths Non-Linear Processor with adaptive suppression threshold and comfort noise insertion Programmable Double-Talk detection threshold Narrow-Band signal detection Selectable/A-Law ITU-T G.711; /A- Law Sign Magnitude; linear 2's complement Adjustable Gain/Loss settings on all channels. Provides the user the flexibility to adjust and optimize the voice and transmit receive levels Carrier-grade voice quality per AT&T Voice Quality Assessment Lab Ideally suited to handle most echo situations Assures operability with V.32/V.32bis/V.34 modem and fax transmissions. Conforms to standards assuring proper public network operation and facilitating system integration

6. Slide 6Copyright : Valiant Communications Limited - 2007 Features & Highlights T1 Voice Echo Canceller - 3U (10 per Chassis) Removes residual echo and minimizes switching effects thereby providing high perceived speech quality Ensure echo canceller maintains excellent performance at all times in the presence of non-echo voice signals. Useful for trunks that have very low echo- returns loss Ensure echo canceller maintains excellent performance at all times in presence of tones or signals including DTMF tones Instability detector suppresses variable pitched ringing or oscillation T1 Circuit by pass on power failure Path change detect permits fast re-convergence when a major change occurs in the echo channel Fully integrated independent 24-channels voice echo canceller. Redundant Power Supply (Optional).

7. Slide 7Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) APPLICATION 1 T1 Echo Canceller ATM or Frame Relay Multi-Service WAN Gateway PSTN WAN ATM or Frame Relay Equipment CPE/PBX T1 To cancel echoes at both ends of the network with two 128ms. unidirectional echo cancellers T1 Echo Canceller VCL - EC128 Tail -end side

8. Slide 8Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Satellite link PBX T1 Echo Canceller T1 Echo Canceller APPLICATION 2 To cancel echoes at both ends of the network with two 128ms. unidirectional echo cancellers Tail -end side VCL - EC128

9. Slide 9Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) ATM or Frame Relay Equipment ATM or Frame Relay Multi-Service WAN Gateway PSTN WAN ATM or Frame Relay Equipment CPE/PBX T1 Echo Canceller * This end hears no echo T1 APPLICATION 3 Tail -end side To cancel the near-end echo with one 128ms. unidirectional echo canceller USER VCL - EC128

10. Slide 10Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) APPLICATION 4 ATM or Frame Relay Equipment ATM or Frame Relay Multi-Service WAN Gateway PSTN WAN T1 Echo Canceller ATM or Frame Relay Equipment CPE/PBX * This end hears no echo USER T1 To cancel the far-end echo with one 128ms. unidirectional echo canceller Tail -end side VCL - EC128

11. Slide 11Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) APPLICATION 5 To cancel echoes at both ends of the network with one 64ms. bidirectional echo canceller. ATM or Frame Relay Equipment ATM or Frame Relay Multi-Service WAN Gateway PSTN WAN T1 Echo Canceller ATM or Frame Relay Equipment CPE/PBX * This end hears no echo USER T1 VCL - EC64B * This end hears no echo

12. Slide 12Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Front Panel View of Echo Canceller Front View (Left to Right)Card Details Part No. Slot 1: PS, Power Supply Card VCL-EC-1295 Slot 2: PS, Power Supply Card VCL-EC-1295 Slot 3 to Slot 12: EC, Echo Canceller Card VCL-EC-1273-T1 (64 ms/128 ms Echo Cancellation) Slot 13: NMS Card VCL-EC-1222

13. Slide 13Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Network Interface - T1 Interface at 1544 Kbps Number of Interfaces2, 1-Input (RJ-45), 1-Output (RJ-45) Line RateT1 - 1.544 Mbps Line CodeB8ZS, AMI (User Selectable) Frame StructureD4, ESF (User Selectable) PCM Encoding Law  Law as per ITU-T G.711 SignalingPass-Through Signaling protocols supported: - 24B (24 Voice Channels) with out-of-band signaling. - C7/SS7 signaling on any user selected time-slot). - 23B+D, PRI ISDN (23 Voice Channels+D Signaling Channel). - Robbed Bit Signaling. - All signaling options are User Selectable PCM Sampling Rate8000 Samples/sec Bit Rate1544 Kbps ± 50 ppm Jitter ToleranceAs per ITU-T G.823 Technical Specifications

14. Slide 14Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Output Jitter< 0.05 UI (in the frequency range of 20Hz to 100 KHz) Nominal Line Impedance100 Ohms Balanced RJ 45 Nominal Pulse Width244 ns Pulse MaskAs per ITU (CCITT) Rec. G.703 Loss and recovery of frame As per clause 3 of ITU (CCITT) G.732 alignment Loss and recovery of As per clause 5.2 of ITU (CCITT) G.732 multiframe Alignment Echo Cancellation Echo Tail CancellationUp to 64ms Bidirectional/128ms Unidirectional - User Selectable Tone DisablerAs per ITU-T G.164, G.165 ERLE (Echo Return Loss >35dB (with 6dB ERL) at -10dBm0 input Enhancement)>65dB with NLP enabled ERL (Echo Return Loss)Selectable Levels Options: 0, 3, 6 dB Technical Specifications

15. Slide 15Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Transmit/Receive Levels Selectable Levels Options: (Programmable)-12, -9, -6, -3,,0 +3, +6, +9 Comfort Noise InsertionUser Selectable - ON/OFF Local Monitoring and ControlRS232 serial interface for Management through a PC COM Port Remote Monitoring and ControlEthernet (10BaseT) interface for remote LAN Management and Control Local and Remote ProvisioningCLI (text commands) and GUI Front Panel Indicators- In SYNC/Failure - Equipment alarm - LEDs for power on/off Power Supply RedundancyOptional: -48V DC Power Supply (1+1) Environmental - Operational0°C to 50°C Humidity5% to 95%, non-condensing Technical Specifications

16. Slide 16Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Input DC voltage-48V DC (nominal ) Range of Input Voltage-40V to -60V DC Output voltages+5V Maximum Full Load Output Current10A at +5V Input Voltage Reversal ProtectionProvided in the card Over Current Protection> 10A for +5V Short Circuit ProtectionCurrent Limit - 10A. Recovers on removal of short Under Voltage< 4.5V Over Voltage5.4V Efficiency at full load>86% Ripple at full load<5mVrms Spike at full load<50mV Power Supply Specifications

17. Slide 17Copyright : Valiant Communications Limited - 2007 Management Port Specifications 10BaseT LAN Management Port (with Telnet) Network Interface RJ-45 Ethernet 10BaseT or 100 BaseT-TX (auto sensing) Compatibility Ethernet Version 2.0 IEEE802.3 Protocols SupportedARP, UDP/IP, TCP/IP, Telnet, ICMP, SNMP, DHCP, BOOTP, TFTP, Auto IP, SMTP and HTTP LEDs10Base-T & 100Base-TX Activity, Full/half duplex ManagementSerial login, Telnet login, GUI EMI Compliance - Radiated and conducted emissions - complies with Class B limits of EN55022:1998 - Direct and Indirect ESD - complies with EN55024:1998 - RF Electromagnetic Field Immunity - complies with EN55024:1998 - Electrical Fast Transient / Burst Immunity - complies with EN55024:1998 - Power Frequency Magnetic Field Immunity - complies with EN55024:1998 - RF Common Mode Conducted Susceptibility - complies with EN55024:1998 T1 Voice Echo Canceller - 3U (10 per Chassis)

18. Slide 18Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Mechanical Specifications Rack MountingStandard 19 Inch. DIN Rack Height133.33 mm. Depth292 mm. Width 482 mm. Weight7.50 (10, T1 Echo canceller) Power Consumption Card in Use Current Power Consumption (in Amps.) (in Watts) Input Voltage = - 48 Volt 1 EC Card + PSU Card + NMS Card0.15 6.0 10 EC Cards + PSU Card + NMS Card0.825 39.6

19. Slide 19Copyright : Valiant Communications Limited - 2007 T1 Voice Echo Canceller - 3U (10 per Chassis) Compliance/Regulatory EMC FCC Part 15 Class Operation ETS 300 019 Class 3.2 Storage ETS 300 019 Class 1.2 Transportation ETS 300 019 Class 2.3 CE Clock Internal (Stratum 3 level) Loop-timed Port A/Port B (User Selectable) Management Port Specifications RS232 COM Port Serial Port: 9.6Kbps (Async). ASCII/VT100/HyperTerminal. 10BaseT Ethernet: Telnet

20. Slide 20Copyright : Valiant Communications Limited - 2007 Valiant’s Echo Canceller Solutions: T1 Voice Echo Canceller - 3U (10 per Chassis) E1 8 x Echo canceller with VQE - Compact 1U Shelf T1 8 x Echo canceller with VQE - Compact 1U Shelf E1 Echo canceller - 3U Version (10 EC’s per Chassis) T1 Echo canceller - 3U Version (10 EC’s per Chassis) E1 Echo canceller - Desktop Version T1 Echo canceller - Desktop Version E1 Echo canceller 1U with Telnet - 1U T1 Echo canceller 1U with Telnet - 1U QUAD E1 Echo canceller (32 EC’s per Chassis) QUAD T1 Echo canceller (32 EC’s per Chassis) DS3 Echo canceller with VQE

21. Slide 21Copyright : Valiant Communications Limited - 2007 Thank you for your attention For more details visit us at our Website at http://www.valiantcom.com T1 Voice Echo Canceller - 3U (10 per Chassis) U.K. Valiant Communications (UK) Ltd 1, Acton Hill Mews, 310-328 Uxbridge Road, London W3 9QN, United Kingdom E-mail: gb@valiantcom.com Website: http://www.valiantcom.com INDIA Valiant Communications Limited 71/1, Shivaji Marg, New Delhi - 110015, India Phone: +91-11 4105 5601, 91-11 4105 5602 Fax: +91-11 4105 5604, 91-11 2543 4300 E-mail: getinfo@valiantcom.com Website: http://www.valiantcom.com U.S.A. Valcomm Technologies Inc. 4000 Ponce de Leon, Suite 470 Coral Gables, FL 33146 United States of America E-mail: us@valiantcom.com Website: http://www.valiantcom.com