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General

The KeyTrunk300 Series offers a cost-effective high-density TDM/RTP streaming board solution for open Computer Telephony (CT) systems. The KeyTrunk300 Series provides a scalable solution capable of processing between 128 and 2,016 channels of TDM traffic per board.

The KeyTrunk300 board supports RTP streaming using standard RTP/UDP/IP/Ethernet protocol encapsulation. It also provides a VoIP stack that includes ARP, ICMP and RTCP functionality.

Various parameters can be adjusted under user control such as the packet size for each channel. The KeyTrunk300 board also supports an IP-Trunking mode whereby multiple TDM streams are dynamically mapped into single RTP packets.

This capability allows to interconnect any number of distributed CT systems together very economically while providing the equivalent of a very large integrated TDM switch.

Multi-Chassis System
(click picture to enlarge)

On-Board Resources

For packetization, the KeyTrunk300 utilizes dedicated ASICs instead of conventional processors. This design choice produces a high density solution that frees up the host CPU to perform other tasks.

Dynamic Trunking

The Dynamic Trunking capabilities of the KeyTrunk300 allow the transport of TDM traffic (T1/E1) over Ethernet LANs or IP networks and the implementation of high-capacity TDM channel interconnects between CT chassis. This mode of operation packetizes multiple TDM channels into one RTP packet to create a trunk. Which is advantageous since it establishes a low latency (~1-2 milliseconds) interconnect between CT chassis and their respective H.1x0 TDM busses.

Dynamic Trunking over Ethernet
(click picture to enlarge)

The dynamic aspect allows the trunks to be continuously resized depending on the number of active channels. When opening dynamic trunks, the desired packetization delay is specified via the KeyTrunk API and the number of frames per packet is adjusted accordingly. Up to 256 trunks can be defined per board. Each trunk can transport up to 255 channels. While the S/W allows to oversubscribe capacity at trunk definition time, the board will monitor its remaining capacity as active channels are added or removed.

Inter-Chassis Clock Distribution

The KeyTrunk300 implements an adaptive TDM synchronization algorithm to propagate a reference across a packet network. The master KeyTrunk board will build and send 10ms G.711 RTP packets at the speed of the reference clock over a special RTP connection. The receiving end will use the RTP time stamp information to estimate the clock ratio.

Physical Interfaces

On the network side, the KeyTrunk300 offers two 100Mbps Ethernet ports. The dual Ethernet can be used as either two independent subnets or in an automatic failover mode that switches traffic to the alternative interface without interruption of in-progress calls. Traffic can be packetized either as VoIP or Voice over Ethernet. On the TDM side, the board connects to the local PCM highways via a ribbon cable or backplane bus, and is compatible with H.100/H.110 industry standard TDM buses. Finally, a 32-bit PCI interface is available, allowing complete control of the board via API.

Applications

The KeyTrunk300 Series can be utilized to build large scalable CT telephony systems by interconnecting together multiple CT chassis. This is especially useful in the implementation of prepaid calling card applications, least cost routing switches, messaging and other similar systems.

Technical Details

Host Interface

• PCI: Universal PCI bus, PCI Rev 2.1
• cPCI: PICMG 2.0, R2.1
• 32 bits, 33 MHz

Software Development Environment

• Key Trunk API
• Windows NT, 2000, XP, 2003
• Linux RH 7.2, 7.3, and 9

Power Requirements (Typical)

• PCI: 11 W
• cPCI: 13 W

Telephony Bus Interface

• H.100 / H.110
• 4096 addressable time slots
• Up to 1008 ch. for PCI
• Up to 2016 ch. for cPCI

IP Network Interface

• Dual port 100Base-T Ethernet on RJ-45
• Protocols: RTP, RTCP, ARP, ICMP, DHCP
• Link protocol: Ethernet (DIX, 802.3, 802.1pQ) 

Dynamic Trunking

• Ethernet and/or IP modes
• Up to 256 Trunks per board
• Up to 255 channels per Trunks
• Clock Distribution algorithm

Environmental

• Operating: 0°C to +50°C
• Storage: -40°C to +70°C
• Humidity: 5% to 85% non-condensing, 95% at +40°C range

Regulatory

CE:

• 89/336/EEC EMC Directive;
• 73/23/EEC Low Voltage Directive.

FCC:

• Part 15 Rules, Subpart B § 15.105

Industry Canada:

• ICES-003 Issue 2

Safety:

• UL 60950 3rd Edition
• CSA 22.2, No 950

General

Namely, these features include:

• Echo Cancellation (128 ms tail-lengths on every ports)
• Voice Quality Enhancement features
• Conferencing (up to 512 ports)
• Voice Activity Detection (VAD) that performs extremely well in double talk conditions - such as speech recognition
• IVR Prompts Playback and Caching
• DTMF Tone Relay

Other features often required for media servers are readily supported, such as IP-Forking (whereby a TDM channel is multicast over more than one IP packet).

The KeyTrunk500 board also supports a mode whereby multiple TDM streams are dynamically mapped into single RTP packets, advantageous for trunking or multi-chassis interconnect is required.  This specialized capability, which emulates TDM trunks (T1/E1), implements high-capacity, low-delay TDM channel interconnect over an Ethernet LAN or an IP network.

The KeyTrunk500 utilizes dedicated ASICs instead of conventional DSPs for both Packetization and Media Processing resources.  This choice of design produces a high density solution on a very small footprint with low power consumption.  Another significant advantage is that all of the resources are available simultaneously, regardless of the usage mix, while minimizing the need for Host CPU cycles.

On the network side, the KeyTrunk500 offers two 100Mbps Ethernet ports.  The dual Ethernet can be used as either two independent subnets or in an automatic failover mode that switches traffic to the alternative interface without interruption of calls in progress.  Traffic can be packetized either as VoIP or Voice over Ethernet.  On the TDM side, the board connects to the local PCM highways via a ribbon cable or backplane bus and is compatible with H.100/H.110 industry standard TDM buses.  Finally, a 32-bit PCI interface is available, allowing complete control of the board via API.

Host Media Processing (HMP).  The KeyTrunk500 Series offers an ideal TDM interface card for HMP systems (see diagram) where it converts TDM streams to IP and performs the necessary media functions such as Tone Relay and Echo Cancellation.  For speech recognition systems, the VAD feature can also be used to further reduce downstream processing.

KT500 in Media Gateways and Media Servers
(click picture to enlarge)

Messaging and Voice-mail Systems:  The KeyTrunk500 card can be used to connect messaging and voice-mail servers over packet networks.  In this case, ADPCM compression can be used to reduce storage requirements and network bandwidth. The VAD function can be used to further reduce the bandwidth for transmission as well as storage requirements.

VoIP Trunking.  The KeyTrunk500 Series offers a complete solution for VoIP trunking applications.  Using the Kallastra ADPCM and dynamic trunking features, a low-delay and highly bandwidth efficient solution is readily available.

Host Interface

• PCI: Universal PCI bus, PCI Rev 2.1
• cPCI: PICMG 2.0, R2.1
• 32 bits, 33 MHz

• Dual port 100Base-T Ethernet on RJ-45
• Protocols: RTP, RTCP, ARP, ICMP, DHCP
• Link protocol: Ethernet (DIX, 802.3, 802.1pQ)

• G.711 with support for A-law/µ-law conversion
•   ASR-friendly Voice Activity Detection (VAD)

• Echo Cancellation: G.168, up to 128 ms echo tail lengths
• Voice Quality Assurance Features
  • Acoustic Echo Control (AEC)
  • Adaptive Noise Reduction (ANR)
  • Adaptive Level Control (ALC)
  • Packet Loss Concealment (PLC)
  • Line Echo Cancellation (LEC)
• Conferencing: up to 512 ports
• Buffer Playout: 130 minutes of on-board, playout buffer storage 
• Tone Relay (RFC2833) - DTMF
• Tone Regeneration - DTMF

• ADPCM G.726 / G.727 with Silence Suppression

• PCI: 11 W
• cPCI: 13 W

• Key Trunk API
• Windows NT, 2000, XP, 2003

• Linux RH 7.2, 7.3, and 9

Telephony Bus Interface

• H.100 / H.110

• 4096 addressable time slots

• Up to 1008 ch. for PCI

• Up to 1008 ch. for cPCI

Dynamic Trunking

• Ethernet and/or IP modes
• Up to 256 Trunks per board
• Up to 255 channels per Trunks
• Clock Distribution algorithm

• Operating: 0°C to +50°C
• Storage: -40°C to +70°C
• Humidity: 5% to 85% non-condensing, 95% at +40°C range

CE:

• 89/336/EEC EMC Directive
• 73/23/EEC Low Voltage Directive.

• Part 15 Rules, Subpart B § 15.105

• ICES-003 Issue 2

• UL 60950 3rd Edition
• CSA 22.2, No 950

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