TE120 Series TE120P / TE121 / TE122 User Manual 601-00010 Rev.
Digium, Inc. 445 Jan Davis Drive NW Huntsville, AL 35806 United States Main Number: 1.256.428.6000 Tech Support: 1.256.428.6161 U.S. Toll Free: 1.877.344.4861 Sales: 1.256.428.6262 www.digium.com www.asterisk.org www.asterisknow.org © Digium, Inc. 2013 All rights reserved. No part of this publication may be copied, distributed, transmitted, transcribed, stored in a retrieval system, or translated into any human or computer language without the prior written permission of Digium, Inc. Digium, Inc.
Compliance Information Compliance information for this product is available at http://www.digium.com/ccs-compliance. Digium, Inc.
Introduction to TE120 Series Documentation This manual contains product information for the TE120 Series of cards (TE120P, TE121, and TE122). Be sure to refer to any supplementary documents or release notes that were shipped with your equipment. The manual is organized in the following manner: Chapter/ Appendix Title Description 1 Overview Identifies your card’s features. This chapter also covers applications and uses for the TE120 Series card in the real world.
Symbol Definitions Caution statements indicate a condition where damage to the unit or its configuration could occur if operational procedures are not followed. To reduce the risk of damage or injury, follow all steps or procedures as instructed. The ESD symbol indicates electrostatic sensitive devices. Observe precautions for handling devices. Wear a properly grounded electrostatic discharge (ESD) wrist strap while handling the device.
Important Safety Instructions User Cautions Servicing. Do not attempt to service this card unless specifically instructed to do so. Do not attempt to remove the card from your equipment while power is present. Refer servicing to qualified service personnel. Water and Moisture. Do not spill liquids on this unit. Do not operate this equipment in a wet environment. Heat.
Service Personnel Cautions Servicing. Disconnect telecommunications network cable before opening the cover or removing the card from the motherboard. Labeling. For safety reasons, only connect equipment with a Telecommunications Compliance label. This includes customer equipment previously labelled Permitted or Certified. Caution. Only connect regulatory equipment (approved for use in your specific country) to the telecommunications network voltage circuit ports. Caution.
TABLE OF CONTENTS Chapter 1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Echo-Cancellation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 What is Asterisk®? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Asterisk as a Phone Switch (PBX) . . . . . . . . . . . . . . . . . . . . . . . . . 16 Asterisk as a Gateway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table Of Contents Configuring T1/E1 Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 Testing Your Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Chapter 4 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Appendix A Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Appendix B Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of Figures Figure 1: Figure 2: Figure 3: Figure 4: Figure 5 : Figure 6 : Figure 7 : Digium, Inc. Sample Legacy Phone Application . . . . . . . . . . . . . .14 Sample IP Phone Application . . . . . . . . . . . . . . . . . . 14 TE120P Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 TE121 Card with Echo Cancellation Module . . . . . . 23 TE122 Card with Echo Cancellation Module . . . . . . 24 Motherboard Slots . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Insert the Card .
List of Tables Table 1: Table A-1: Table B-2: Digium, Inc. Card Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 RJ45 Telco Port Connector . . . . . . . . . . . . . . . . . . . .56 Maximum Power Consumption . . . . . . . . . . . . . . . . .
Chapter 1 Overview The Digium TE120 Series cards are a T1/E1 capable card series created for voice. They support industry standard protocols, including Robbed Bit Signaling (also known as CAS or Channel Associated Signaling), CCS (Common Channel Signaling), E&M, and Primary Rate ISDN (PRI). The TE120 Series cards are capable of running in E1, T1, or J1 modes.
Chapter 1: Overview Voice Modes: PRI CPE and PRI NET – NI1 – NI2 – EuroISDN – 4ESS (AT&T) – 5ESS (Lucent) – DMS100 – Q.SIG E&M – Wink – Feature Group B – Feature Group D FXO and FXS – Ground Start – Loop Start – Loop Start with Disconnect Detect The TE120 Series cards can be used to connect your Asterisk machine to the PSTN world, your channel bank, or even another PBX. This is accomplished via a T1/E1 interface.
Chapter 1: Overview Asterisk Server TE12X Internet T1 Legacy PBX Legacy Phones Remote offices Figure 1: Sample Legacy Phone Application Eth LAN Switch TE12X T1 CLEC Asterisk Server IP Phones Figure 2: Sample IP Phone Application Digium, Inc.
Chapter 1: Overview Echo-Cancellation Users connecting their TE120 Series cards to the PSTN or other devices are likely to be placing calls that will result, at some point, in an unbalanced 4-wire/2-wire hybrid. The result of this hybrid is the reflection of a near-end echo to the calling party. Elimination of this echo is the responsibility of echo cancellation. The TE120 Series cards, unless otherwise equipped, utilize Asterisk to perform software-based echo cancellation.
Chapter 1: Overview What is Asterisk®? Asterisk is the world’s leading open source telephony engine and tool kit. Offering flexibility unheard of in the world of proprietary communications, Asterisk empowers developers and integrators to create advanced communication solutions...for free. Asterisk is released as open source under the GNU General Public License (GPL), and it is available for download free of charge.
Chapter 1: Overview architecture allows it to convert between a wide range of communications protocols and media codecs. Asterisk as a Feature/Media Server Need an IVR? Asterisk’s got you covered. How about a conference bridge? Yep. It’s in there. What about an automated attendant? Asterisk does that too. How about a replacement for your aging legacy voicemail system? Can do. Unified messaging? No problem. Need a telephony interface for your web site? Okay.
Chapter 1: Overview Asterisk Everywhere Asterisk has become the basis for thousands of communications solutions. If you need to communicate, Asterisk is your answer. For more information on Asterisk, visit http://www.asterisk.org or http://www.digium.com. Digium, Inc.
Chapter 2 Card Installation This chapter provides the following information: Unpacking the Card on page 20 Shipment Inspection on page 21 Identifying Features on page 21 T1/E1 Selection on page 21 Slot Compatibility on page 25 Hardware Installation on page 27 Software Installation on page 29 Installing Asterisk on page 35 Note: The TE120 Series card installation instructions are written so that they will apply to any card in the series.
Chapter 2: Card Installation Unpacking the Card When you unpack your card, carefully inspect it for any damage that may have occurred in shipment. If damage is suspected, file a claim with the carrier and contact your reseller from which the card was purchased, or contact Digium Technical Support at 1.256.428.6161. Keep the original shipping container to use for future shipment or proof of damage during shipment. Note: Only qualified service personnel should install the card.
Chapter 2: Card Installation Shipment Inspection The following items are included in shipment of the TE120 Series: TE120 Series card (TE120P / TE121 / TE122) Identifying Features Your TE120 Series card has one RJ45 port and two status LEDs. The port is used for connecting T1, E1, or J1 cables. The two LEDs serve as a status LED and an amber loop-back LED. The card includes a strap for selecting either T1 or E1 line mode. See Figure 3 on page 22 to locate these features.
Chapter 2: Card Installation T1/E1 Jumper Status LED Loopback Mode LED Port 1 PCI Connector Figure 3: TE120P Card Digium, Inc.
Chapter 2: Card Installation Status LED Loopback Mode LED Echo Cancellation Module Port 1 PCI Express Connector Figure 4: TE121 Card with Echo Cancellation Module Digium, Inc.
Chapter 2: Card Installation Status LED Echo Cancellation Module Loopback Mode LED Port 1 PCI Connector Figure 5: TE122 Card with Echo Cancellation Module Caution. Only qualified service personnel should continue with hardware installation and configuration of the TE120 Series card. Non-qualified personnel should not attempt to perform these functions themselves. Digium, Inc.
Chapter 2: Card Installation Slot Compatibility Check the type of card you received to be sure it is compatible with your PCI slot. To determine which slot you have, identify it by comparing it to those shown in Figure 6 on page 25. Slot Number: 0: AGP Pro Slot 1: 64-bit 5.0 volt PCI Slot 2: 64-bit 3.3 volt PCI Slot 3: 32-bit 5.0 volt PCI Slot 4: PCI Express X1 Slot Slots 0 1 2 3 4 Figure 6: Motherboard Slots Digium, Inc.
Chapter 2: Card Installation The TE120 and TE122 cards are 32-bit 33MHz cards keyed for universal 3.3 volt or 5.0 volt operation and works in any PCI 2.2 (or greater) compliant slot. This means that in the motherboard shown in Figure 6, the TE120 Series and TE122 cards will fit into Slots 1, 2, or 3 (PCI slots), but will not fit into Slot 0 (AGP slot). The TE121 card is a PCI Express card. Slot 4, illustrated above, is a 1 lane (X1) PCI Express compliant slot.
Chapter 2: Card Installation Hardware Installation 1. Now that you are acquainted with the TE120 Series cards, power down your computer and unplug it from its power source. 2. Attach a static strap to your wrist and open the case. 3. Check the jumper setting to ensure it matches your equipment configuration. Setting the jumper with the jumper strap on enables the ports for E1. Setting the jumper with the jumper strap off enables the ports for T1. 4.
Chapter 2: Card Installation 6. Plug the T1 or E1 equipment cable into the RJ45 port. Caution. This unit must be connected to the Telecommunications Network in your country using an approved line cord (e.g. for Australia use only line cords complying with AS/CA S008:2010). Caution. This unit must be connected only to the appropriate Telecommunications Network port (as approved for use in your specific country). Digium, Inc.
Chapter 2: Card Installation Software Installation Digium hardware requires drivers and libraries that are not integrated with the Linux kernel. Digium hardware is only supported under Linux. Digium recommends CentOS, Debian, Red Hat, and Ubuntu distributions of Linux. However, many other distributions are supported by Digium Technical Support. Digium’s software, including drivers and application software, may be obtained from Digium’s download server at: http://downloads.digium.
Chapter 2: Card Installation installed any of these, Digium recommends that you upgrade to the latest “-current” version of each. If you are using the 1.4.x series of Asterisk, you will need Asterisk 1.4.22 or newer. Digium, Inc.
Chapter 2: Card Installation 1. After the machine has booted to Linux, log in and execute the following command to list the devices detected by the PCI bus: # lspci -n 2. Confirm that the output from lspci lists a device with Digium’s PCI vendor ID which is “d161”. The screen output should be similar to the following: 0000:01:00.0 0200: ISDN controller: Unknown device d161: Note: The output from lspci may or may not state “Unknown device”. If it does, this does not indicate a problem.
Chapter 2: Card Installation Table 1: Card Identifiers Model TE120P TE121 TE122 Identifier 0120 8000 8001 A Digium TE120 Series (TE120P / TE121 / TE122) card identifier should be listed. If a matching card identifier is not listed, then your machine is not PCI 2.2 (or higher) or PCI Express compatible, and the card will not work with your motherboard. 3. Download the latest version of libpri. Substitute the version of libpri for the X.X in the command line below.
Chapter 2: Card Installation command lines below. # # # # tar -zxvf libpri-X.X-current.tar.gz cd libpri-X.X.X/ make make install Note: There is no coorelation between the versioning of libpri and Asterisk. The libpri 1.4 branch will function with the Asterisk 1.6 branch. 5. Download the latest DAHDI drivers with tools. DAHDI is available for download from: http://downloads.digium.com/pub/telephony/dahdi-linux-complete # wget http://downloads.digium.
Chapter 2: Card Installation 6. Expand the downloaded file, compile its contents, and install the drivers and tools. Substitute the version of DAHDI for the X.X.X in the command lines below. # # # # # tar -zxvf dahdi-linux-complete-current.tar.gz cd dahdi-linux-complete-X.X.X+X.X.X make make install make config Note: Executing ‘make config’ will install an init script and symlinks which will allow you to start and stop DAHDI as a service. Digium, Inc.
Chapter 2: Card Installation Installing Asterisk If you wish to use Asterisk with your new hardware, you can follow the instructions below. 1. Download the latest release version of Asterisk, either 1.4.22 (or later), 1.6.0.1 (or later), or 1.8.0 (or later). Substitute the version of Asterisk for the X.X in the command below. Asterisk is available for download from: http://downloads.digium.com/pub/telephony/asterisk # wget http://downloads.digium.com/pub/telephony/ asterisk/asterisk-X.X-current.tar.gz 2.
Chapter 2: Card Installation 3. If this is the first Asterisk installation on this system, you should install the sample configuration files. To do this, run: # make samples Note: Running this command will overwrite, after making a backup copy, any older Asterisk configuration files that you have in the /etc/ asterisk directory. If your installation has failed, it may be because you are missing one or more of the build dependencies, the kernel headers, or the development tools.
Chapter 3 Configuration The TE120 Series cards have a variety of configuration options. This chapter provides configurations for PRI, channel bank, and E&M wink. These sample configurations are provided to assist you in familiarizing yourself with the flexibility of editing the configuration files to meet your specific needs. The list of possible configurations is too expansive to cover in this user manual. Digium, Inc.
Chapter 3: Configuration Configuring Card Features You will need to modify the chan_dahdi.conf file which is located in the /etc/asterisk directory in order to configure the essential features of your card. This file is the configuration layer between DAHDI and Asterisk. Switchtype: national: dms100: 4ess: 5ess: euroisdn: ni1: qsig: National ISDN 2 (default) Nortel DMS100 AT&T 4ESS Lucent 5ESS EuroISDN Old National ISDN 1 Q.SIG Echocancel: Echo Cancellation is enabled in chan_dahdi.
Chapter 3: Configuration or echocancel = 256 (this sets 256 taps or 32ms) Users of Digium's HPEC software have the following additional options: echocancel = 512 (this sets 512 taps or 64ms) or echocancel = 1024 (this sets 1024 taps or 128ms) Please note that HPEC consumes extremely high amounts of CPU MIPS that increase as the number of taps are increased. Audio quality issues may result from choosing a taps length greater than the server's ability to process the echo in real-time.
Chapter 3: Configuration Signalling: pri_cpe for CPE side. pri_net for NET side. If you have a T1 PRI, add these lines to the following lines of the sample file.
Chapter 3: Configuration Configuring T1/E1 Lines 1. Begin by opening the system.conf file from the /etc/dahdi directory. 2. Specify the two letter country code for your loadzone and defaultzone. This will preload tone zone data and specify a default tone zone for your interfaces. The following is a typical setup for a telco in the US: loadzone = us defaultzone = us 3. Configure the SPAN Map. You will need to define a span.
Chapter 3: Configuration Timing: This determines how timing is handled by the card. 0 - This span is not used to determine timing. If all spans on the card are set to 0, the card will use its internal clock as the timing source. 1, 2, 3, ... - A value greater than 0 will cause the span to attempt to recover a clock source from the line for the entire card to use as timing.
Chapter 3: Configuration Coding: T1 coding can be AMI or B8ZS. E1 coding can be AMI or HDB3. E1 can also have the extra flag CRC4 at the end for CRC4 checking. Yellow: The optional yellow flag can be added at the end for transmitting a yellow alarm when no channels are open. The following is a typical setup for a telco in the US: span => 1,1,0,esf,b8zs In Europe: span => 1,1,0,ccs,hdb3 4. Specify the channel definitions.
Chapter 3: Configuration any channel. So, it is very important that you specify one in the system.conf file if you do not have hardware echo cancellers and need echo cancellation. The format is: echocanceller = , A list of valid echo cancellers are specified in the sample system.conf file. The following is a typical setup for a T1 PRI in the US using softwarebased echo cancellation: echocanceller = mg2,1-23 Digium, Inc.
Chapter 3: Configuration First Example: Channel Bank The Channel Bank in this example has 24 FXS ports. In this configuration, the system.conf is set for the card to provide timing to the channel bank and fxoks is set for 24 stations. Set chan_dahdi.conf to mirror the configuration with signalling = fxo_ks and define it for channels 1-24. /etc/dahdi/system.conf: loadzone = us defaultzone = us span = 1,0,0,esf,b8zs fxoks = 1-24 echocanceller = mg2,1-24 /etc/asterisk/chan_dahdi.
Chapter 3: Configuration Second Example: E&M Line In the E&M Line configuration, the system.conf is set for the card to take timing from the telco on E&M with wink while chan_dahdi.conf mirrors the configuration. Feat_D is a type of E&M with wink that accepts DID, but there are many E&M options; E&M_W, E&M, Feat_B, etc. /etc/dahdi/system.conf: loadzone = us defaultzone = us span = 1,1,0,esf,b8zs e&m = 1-24 echocanceller = mg2,1-24 /etc/asterisk/chan_dahdi.
Chapter 3: Configuration Third Example: PRI By configuring the card for a T1 PRI line in system.conf, you acquire 23 bearer (B) channels for voice on the first 23 channels, and 1 delta (D) channel for signalling information on the 24th channel. In the chan_dahdi.conf file, define pri_cpe as the signalling type to act as the client side. Define the switch type you are connecting to as national. You will then have 23 voice channels for Asterisk. PRI T1: /etc/dahdi/system.
Chapter 3: Configuration PRI E1: /etc/dahdi/system.conf: loadzone = es defaultzone = es span = 1,1,0,ccs,hdb bchan = 1-15,17-31 dchan = 16 echocanceller = mg2,1-15,17-31 /etc/asterisk/chan_dahdi.conf: group = 1 echocancel = yes signalling = pri_cpe switchtype = euroisdn context = incoming channel = 1-15,17-31 Digium, Inc.
Chapter 3: Configuration Testing Your Configuration 1. Load DAHDI drivers into the kernel using the modprobe utility. The appropriate driver for the TE120 Series cards is wcte12xp. Users in all countries except Australia should use the following modprobe command: # modprobe wcte12xp # dahdi_cfg -vv 2. Run dahdi_tool from the command line and see if the span turns green for each span you have connected. # dahdi_tool 3. Execute the following Asterisk command to see if the span came up successfully.
Chapter 4 Troubleshooting This chapter provides frequently asked questions as identified from Digium Technical Support and possible resolutions. Multiple resources are available to obtain more information about Asterisk and Digium products. These resources are listed on page 55. What do the Status LED colors indicate? Green - Card is in-sync with the far end. Yellow - Card is synchronizing or is receiving a red alarm from the far end.
Chapter 4: Troubleshooting 2. Then type reload in the Asterisk console and call in. You should see the DID come in on your T1/E1 line. My D Channel seems to go up and down. Check to be sure you have set your timing parameters correctly. Also, check the common causes of problems for a T1. See the Common Fixes for all cards, page 54. I have trouble dialing out. It seems that one type of dialing works (local, long distance, international), but another does not.
Chapter 4: Troubleshooting I am still having problems and the telco tells me it is my equipment. The first thing to do in this situation is to test your equipment. 1. Plug in a loopback cable. (A loopback cable is a cable that has pin 1 going to pin 4 and pin 2 going to pin 5.) Plug the cable into the span and wait for its LED to turn green. 2. Stop Asterisk and edit system.
Chapter 4: Troubleshooting 4. # ./patlooptest /dev/dahdi/1 60 The first argument in the patlooptest command is the device for the channel number you want to test. You should always test the first channel of a span. The second argument is the duration in seconds to run the test. This runs a pattern looptest for 60 seconds. If you receive any failures, it is possible you have a bad card and will need to call Digium Technical Support at 1.256.428.
Chapter 4: Troubleshooting Common Fixes for all cards 1. Check to see if the X Window System (e.g. X.Org Server) is running by entering the following: # ps aux | grep X If the X Window System is running, stop the application since it may cause a conflict with Asterisk. 2. Check to see if your PATA IDE hard drives are running with DMA levels set. Advance user can perform an hdparm on your hard drive interface.
Chapter 4: Troubleshooting Where can I find answers to additional questions? There are several places to inquire for more information about Asterisk Digium products: 1. Digium Technical Support at 1.256.428.6161, or Toll Free in the U.S. (1.877.344.4861), is available 7am-8pm Central Time (GMT -6), Monday - Friday. 2. Asterisk users mailing list (asterisk.org/lists.digium.com). 3. IRC channel #asterisk on (irc.freenode.net).
Appendix A Pin Assignments The communication port on the TE120 Series card bracket is an 8-pin RJ45 port. The pin assignments are identified in Table A-1. Table A-1: RJ45 Telco Port Connector Pin 1 Pin 8 Digium, Inc.
Appendix B Specifications This appendix provides specifications, required environmental conditions, and maximum power consumption for the TE120 Series cards. Physical (All Cards). Size: Weight: 4.82” × 2.175” × 0.63” (12.2 x 5.5 x 1.6 cm) PCB size, does not include the PCI bracket 2 oz (57g) Interfaces. Local Loop Access: E1, T1, J1, PRI; RJ45 (TE120P and TE122) - PCI Bus: 3.3V or 5V bus slot, half-length slot minimum size, 33MHz minimum bus speed, compliant with PCI 2.2 or greater.
Appendix B: Specifications Hardware and Software Requirements. 800-Mhz Pentium III or better 64MB RAM Available PCI (TE120P and TE122) or PCI-E (TE121) Slot Table B-2: Maximum Power Consumption Model Digium, Inc. Power TE120P 3.3V 5V 1.5 Watts 0.1Watt TE121 3.3V 2.0 Watts TE121B 3.3V 3.0 Watts TE122 3.3V 5V 1.5 Watts 0.1Watt TE122B 3.3V 5V 2.5 Watts 0.
Appendix C Glossary and Acronyms ACD Automatic Call Distribution A technology that distributes incoming calls to a specific group of devices that are associated to agents. Asterisk's Queue application performs automatic call distribution. ANSI American National Standards Institute An organization which proposes and establishes standards for international communications. asynchronous Not synchronized; not timed to an outside clock source.
Appendix C: Glossary and Acronyms bit The smallest element of information in a digital system. A bit can be either a zero or a one. bps bits per second A measurement of transmission speed across a data connection. BRI Basic Rate ISDN broadband Broadband transmission shares the bandwidth of a particular medium (copper or fiber optic) to integrate multiple signals. The channels take up different frequencies on the cable, integrating voice, data, and video over one line.
Appendix C: Glossary and Acronyms Cat5E Category of Performance for wiring and cabling. Category 5 Enhanced wiring supports signal rates up to 100 MHz but adheres to stricter quality specifications. CLEC Competitive Local Exchange Carrier A term for telephone companies established after the Telecommunications Act of 1996 deregulated the LECs. CLECs compete with ILECs to offer local service. See also LEC and ILEC. CO Central Office The CO houses local switching equipment.
Appendix C: Glossary and Acronyms DS0 Digital Signal, Level 0 A voice grade channel of 64 kbps. The worldwide standard speed for digitizing voice conversation using PCM (Pulse Code Modulation). DS1 Digital Signal, Level 1 1.544 Mbps in North America (T1) and Japan (J1) -up to 24 voice channels (DS0s), 2.048 Mbps in Europe (E1) - up to 32 voice channels (DS0s). DS1/T1/E1 lines are part of the PSTN. DS3 Digital Signal, Level 3 T3 in North America and Japan, E3 in Europe.
Appendix C: Glossary and Acronyms full duplex Data transmission in two directions simultaneously. FXO Foreign Exchange Office Receives the ringing voltage from an FXS device. Outside lines are connected to FXO ports. FXS Foreign Exchange Station Initiates and sends ringing voltage. Phones are connected to FXS ports. G.
Appendix C: Glossary and Acronyms HDLC High-Level Data Link Control A bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO). IAX Inter-Asterisk eXchange The native VoIP protocol used by Asterisk. It is an IETF standard used to enable VoIP connections between Asterisk servers, and between servers and clients that also use the IAX protocol. iLBC internet Low Bitrate Codec A free speech codec used for voice over IP.
Appendix C: Glossary and Acronyms LED Light-emitting Diode Linux A robust, feature-packed open source operating system based on Unix that remains freely available on the internet. It boasts dependability and offers a wide range of compatibility with hardware and software. Asterisk is supported exclusively on Linux. loopback A state in which the transmit signal is reversed back as the receive signal, typically by a far end network element.
Appendix C: Glossary and Acronyms NT Network Termination A device connecting the customer's telephone or data equipment to the local ISDN exchange carrier's line. NT devices are connected to TE devices. PBX Private Branch Exchange A smaller version of a phone company’s large central switching office. Example: Asterisk. PCI peripheral component interconnect A standard bus used in most computers to connect peripheral devices.
Appendix C: Glossary and Acronyms PRI Primary Rate ISDN PSTN Public Switched Telephone Network A communications network which uses telephones to establish connections between two points. Also referred to as the dial network. PTMP Point-to-Multipoint A connection where data is broadcast between more than two endpoints. PTP Point-to-Point A connection restricted to two endpoints.
Appendix C: Glossary and Acronyms RJ11 A six-pin jack typically used for connecting telephones, modems, and fax machines in residential and business settings to PBX or the local telephone CO. SIP Session Initiation Protocol An IETF standard for setting up sessions between one or more clients. It is currently the leading signaling protocol for Voice over IP, gradually replacing H.323. T1 A dedicated digital carrier facility which transmits up to 24 voice channels (DS0s) and transmits data at 1.544 Mbps.
Appendix C: Glossary and Acronyms telco A generic name which refers to the telephone companies throughout the world, including RBOCs, LECs, and PTTs. tip and ring The standard termination on the two conductors of a telephone circuit; named after the physical appearance of the contact areas on the jack plug. twisted pair Two copper wires commonly used for telephony and data communications.
