Westell DS1 Network Interface Unit

Transcription

1 Section A Equipment Issue A Rev. D, July 2008 Westell DS1 Network Interface Unit CLEI* Code: T1SMM055AA CONTENTS PAGE # 1. GENERAL APPLICATIONS CIRCUIT/FUNCTIONAL DESCRIPTION OPTIONS & FEATURES STALLATION TESTG & TROUBLESHOOTG CUSTOMER & TECHNICAL SERVICES WARRANTY & REPAIRS SPECIFICATIONS GENERAL 1.1 Document Purpose This document describes the Westell DS1 Network Interface Unit (NIU), shown in Figure 1. Table 7 lists other models in the same product family. 1.2 Document Status Whenever this practice is updated, the reason will be stated in this paragraph. Revision D updates the company contact information. Revision C updated the description of S3 in Figure 9 and includes a format update. Revision B updated the S4 silkscreen labels. 1.3 Product Purpose and Description The Westell DS1 Network Interface Unit (NIU) serves as the network interface between a T1 metallic span (or other DS1 facility) and the Customer Premises Equipment (CPE). The primary purpose of the NIU is to provide a maintenance loopback for T1 facilities. The can be optioned to either regenerate or pass the T1 bit stream in the transmit and/or receive paths. The NIU monitors the incoming T1 bit stream for control codes from the network and takes the appropriate action, such as loopback, upon detecting these codes. These codes can be either inband patterns or bit-oriented messages in the ESF Facility Data Link. 1.4 Product Mounting The is half the width of a standard 400-type NIU and mounts in a 200 MECHANICS mounting assembly or shelf. The NIU makes electrical connection to the Facility and CPE sides of the circuit through a 56-pin card-edge connector on the mounting assembly using industry-standard pin assignments. The NIU mounting assembly is usually mounted on an equipment backboard at the customer location, after the building entrance terminal and primary protection. Westell offers a wide range of single and multiple-slot mounting assemblies DS1 NIU TP1 TP2 A O UT M O M I N PWR MAN I N M O M O UT Figure 1. Front View of that are available in both backboard (wall) and rack mount versions for NIUs. In some applications it may be desirable to situate the NIU in outside plant (OSP) cabinets or enclosures. The NIU is fully qualified for operating over the temperature range of -40 to +65 C (temp hardened). For these applications, Westell also offers a range of pre-wired compact OSP enclosures. 1.5 Product Features The NIU offers the following features. Adjustable transmit-path signal limiter protects the network from cross talk or regenerator overload due to mis-optioned CPE O Remote Loopback activation/deactivation via inband loop up/loop down codes or can be controlled locally via front panel push button switch Automatic detection of unframed, SF or ESF framed loopback codes Regenerates the T1 bit stream while in loopback Loopback path Line Build Out of 0, 7.5, 15 or 22.5 db Copyright 2008 Westell, Inc. All rights reserved. *CLEI is a trademark of Telcordia Technologies. 200 MECHANICS is a registered trademark of Westell, Inc. Page 1 of 12

2 Section A Rev. D 22.5dB 15dB 7.5dB LE RPTR NIU 1dB Network Interface CPE Figure 2a. Maximum Section Loss with & Regenerators Out LE RPTR 30dB NIU 15dB Network Interface 7.5dB CPE Figure 2b. Maximum Section Loss with & Regenerators In Figure 2. Typical Application Loopback Timeout feature of 60 minutes; Can be disabled locally via switch or remotely via control codes Continuously monitors the transmit (customer-side) and receive (facility-side) paths for loss of signal Unit can be configured to enter loopback or send AIS (Alarm Indication Signal) or CDI (Customer Disconnect Indication) toward the network upon detecting a loss-ofsignal in transmit path; Feature can be overridden or changed remotely via codes Powered from the span or from an external local supply Operates over the -40 to +65 C range allowing use in outside plant cabinets and enclosures Internal per-circuit fusing Front-panel test points for measuring span current Front-panel LED indicators for: PWR (Power - green LED) (Loopback - yellow LED) (Receive Loss Of Signal - red LED) (Transmit Loss Of Signal - red LED) Monitor jacks on the input ports Breaking-type access jacks on all ports 2.1 Transmission Design, Disabled Normal design parameters allow from 0 to 15 db of loss from the last repeater in the span to the network interface, and a maximum of 7.5 db of loss for internal wiring to the CPE. This represents a total loss of 22.5 db as shown in Figure 2a. 2.2 Transmission Design, Enabled If the maximum loss objectives described in Paragraph 2.1 cannot be achieved, the NIU provides the option to regenerate the signal in the transmit and/or receive paths. In this mode the NIU additionally functions as the last span repeater", allowing the loss from the previous repeater to the NIU to be up to 30 db. - NOTE - Local design practices or other span design considerations may restrict this loss to less than 30 db. The NIU with Regenerator is shown in Figure 2b. 2.3 Power The NIU can be powered either from the T1 span or from a local external supply. When span powered, the NIU has a nominal voltage drop of 15 Volts (250 Ohms at 60 ma). When locally powered, the external supply should be capable of supplying 22 to 56 Vdc and can be positive or negative ground referenced. This allows the NIU to operate from +24 Vdc supplies at certain wireless and PCS (personal communication service) sites. In the local power mode, the NIU completes the T1 span simplex power loop and drops negligible span voltage. 3. CIRCUIT/FUNCTIONAL DESCRIPTION 2. APPLICATIONS The NIU has several applications, as described in the following paragraphs. The provides a maintenance interface between the DS1/T1 facility and the customer interface, see Figure 2. It also provides loopback and local test access to aid in sectionalizing telco span vs. CPE problems. The NIU can be configured to be passive to the DS1 signal or can be configured as the last repeater in the span and regenerate the DS1 signal. 3.1 Normal Operation The following paragraphs describe the operation of the NIU during normal operation. Figure 3 provides a simplified view of the circuit during normal operation and should be referred to during this discussion. For additional details refer to Figure 8, the Block Diagram. 3.2 Receive Path The receive bipolar T1 bit stream from the facility enters the NIU on the port, through an overvoltage protection 2

3 Rev. D Section A MON 7 13 T R DISABLE ENABLE S4-2 CT1 CR TELCO T1/DS1 FACILITY 41 T1 47 R1 S3 LOS CONTROL CODE S1 DISABLE ENABLE LOS MON CT CR CUSTOMER NETWORK TERFACE (CPE) Figure 3. Transmission Path During Normal Operation MON 7 13 T R LOOPBACK CT1 CR TELCO T1/DS1 FACILITY 41 T1 47 R1 LOS LOS O S1 ENABLE CT 55 S CR 49 S LOOPBACK O MON Figure 4. CONTROL CODE DISABLE Transmission Path During Normal Loopback Operation CUSTOMER NETWORK TERFACE (CPE) circuit and is transformer coupled to the receive path circuitry. The receive path is continuously monitored for loss of signal and control codes by the detectors as shown in Figure 3. If a loss of signal is detected in the receive path for more than 150 ms, a loss-of-signal condition is declared and the front-panel LED lights. 3.3 Receive Channel Regeneration The NIU provides the option to either regenerate or transparently pass the incoming T1 signal toward the customer network interface. This feature is controlled by option switch S4-2,. The output is then transformer coupled to the port. 3.4 Transmit Path The T1 bit stream from the CPE is routed into the NIU via the port. The transmit path is continuously monitored by a loss-of-signal detector. If a loss of signal is detected in the transmit path for more than 150 ms, a loss-of-signal condition is declared and the front-panel LED lights. 3.5 Transmit Channel Regeneration The NIU provides the option of regenerating or transparently passing the transmit path signal toward the facility. The transmit path regenerator feature is controlled by switch S1,. - NOTE - When the is set to, the Signal Limiter circuit must be set to Signal Limiter The Signal Limiter limits the peak amplitude of the transmit path signal to the facility. It effectively prevents far-end cross 3

4 Section A Rev. D MON 7 13 T R CT1 CR TELCO T1/DS1 FACILITY LOS CONTROL CODE CDI/AIS GENERATOR LOS CUSTOMER NETWORK TERFACE CPE 41 T1 47 R1 S3 S2 O CT CR LOOPBACK O MON Figure 5. Transmission Path During a -(AIS/CDI) talk and over driving of the last span repeater in situations where the O in the customer CSU is set incorrectly. The Signal Limiter has no affect on the customer signal when the CSU O is set correctly. The Signal Limiter is controlled by S3, and limits the signal as shown in Table 1. These limits are approximate and are also dependent on the signal s ones-density and test set type. The output of the Signal Limiter is transformer coupled toward the facility via the port. S3 Setting Peak Voltage Limit Approx. Equivalent Level 0 db No Limit No Limit 7.5 db 1.2 to 1.5 V -3 to -5 dbdsx 15 db 0.6 to 0.75 V -5.5 to -12 dbdsx Table 1. Signal Limiter Limits 3.7 Loopback The loopback function is used during maintenance and circuit troubleshooting to verify the integrity of the DS1 facility up to and including the NIU. The NIU performs a dual loopback, one is toward the T1 facility and the other is toward the customer equipment. These loopbacks are metallic and effectively verify all active components of the NIU. Figure 4 provides a simplified view of the circuit during loopback and can be referred to during this discussion. For additional details see Figure Loopback Activation/Deactivation Loopback activation/deactivation can be accomplished by one of three ways: 1. remotely, via control codes in the DS1 signal from a network test location, 2. locally, via the front-panel MAN push button switch, or 3. automatically, when the NIU detects a loss of signal from the CPE (S6 dependent) Remote Loopback Operation Remote loopback activation/deactivation is done from a test center by sending inband or ESF control codes toward the NIU. See Table 2. Function Code Sequence Type Activate (Loop-Up) Deactivate (Loop-Down) 60 Minute Loopback Time-out Disable Unframed, SF or ESF ESF Data Link Unframed, SF or ESF ESF Data Link Unframed, SF or ESF ESF Data Link, or ESF Data Link Notes: 1. Right-most bit first. 2. T-Berd, Sunrise, or similar test sets. 3. Phoenix test sets. Table 2. Loopback Control Codes Inband Control Codes Inband codes are repetitive patterns at the Mb rate and may be unframed, SF or ESF framed and must be applied for a minimum of five seconds ESF Control Codes ESF codes are bit-oriented messages in the ESF DataLink. The message must be received for a minimum of four consecutive error-free repetitions (approx. 16 ms) Dual Loopback Transmission Path When in loopback, the received signal from the DS1 facility is regenerated to 0 dbdsx and passed through an O circuit that provides 0, 7.5, 15 or 22.5 db of loss to meet T1 facility design requirements. During loopback the customer signal is also looped back toward the customer as shown in Figure 4. 4

5 Rev. D Section A Loopback Timeout During a code-activated loopback, the unit provides a Loopback Timeout feature, controlled by switch S4-1, that automatically releases the unit from loopback after 60 minutes. During a timed loopback condition, the LED will flash. Loopback can be released prior to the 60-minute timeout expiration period by sending loopdown code or by pressing the front-panel MAN switch, S5. With S4-1 set to disable, the NIU will remain in loopback until a loop-down code is received or until the MAN switch is pressed. When the Loopback Timeout feature is disabled, and the unit is put into loopback, the LED will be lit continuously. - NOTE - The Loopback Timeout can also be disabled remotely via control codes Remote Loopback Timeout Disable The Loopback Timeout feature can be remotely disabled if testing will exceed the 60-minute expiration period. When in loopback, the timeout feature is disabled by sending the SF code or the ESF code The NIU will now remain in loopback until a loop down code is sent or until the MAN switch is pressed Manual Loopback The NIU can be placed into loopback manually by pressing the front-panel MAN switch, S5. When the NIU is placed in manual loopback, the loopback will not timeout regardless of the setting of S4-1 and will remain in loopback until S5 is pressed a second time or until loopdown code is received Loss of Signal from Customer Interface The NIU continuously monitors the DS1 signal from the CPE for loss of signal. Upon detecting a loss of signal in the transmit path (), the front-panel LED will light and the NIU will automatically perform one of the following: 1. activate loopback, 2. send CDI toward the network, or 3. send AIS toward the network. The specific action taken on a is dependent on the setting of S6 and each action is described in detail in the following paragraphs. - NOTE - The NIU can be remotely queried to determine the present setting of the mode as well as remotely toggled to change the setting/configuration. See paragraphs through and Figure 6 for details Loopback (S6-) With S6 set to, the NIU, upon detecting a loss of signal from the CPE, will enter the loopback state as shown in Figure 4 and light the and LEDs. When in the Loopback mode, loopback will not time out nor can it be manually released via the front-panel MAN push button. When the CPE signal is restored, the NIU will return to normal (idle) operation AIS (S6-AIS) With S6 set to AIS, the NIU, upon detecting a loss of signal from the CPE, will light the LED and send an unframed all ones-signal AIS toward the network as shown in Figure 4. When the CPE signal is restored the NIU will return to normal (idle) operation CDI (S6-CDI) With S6 set to CDI, the NIU, upon detecting a loss of signal from the CPE, will light the LED and send a CDI code toward the network as shown in Figure 5. When CPE signal is restored, the NIU will return to normal operation. The specific type of CDI signal sent toward the network is a function of the DS1 signal received from the network. If the received signal is SF, the CDI signal will be SF and provide a repeating pattern in each of the 24 DS0 time slots, If the received signal is ESF, the CDI signal will be ESF and provide a repeating pattern in each of the 24 DS0 time slots. In addition, the ESF Data Link will contain the ESF yellow alarm signal , interrupted each second with a 100ms burst of LAPD idle code , If no signal is received from the network or if the signal is unframed, the NIU will default to the SF CDI mode /CDI/AIS Mode When the NIU enters one of the modes (, AIS or CDI) due to a loss of signal from the customer, the NIU will assume the transmission path as shown in Figure 4 (for loopback) or Figure 5 (for either AIS or CDI). At this point, the test person can: 1. Take no action. When the customer signal is restored the NIU will return to normal operation. 2. Send a loop-down code. This will place the NIU into a override mode and allow testing through the NIU to the customer interface. Also, while in the Override mode, a 60-minute timer is activated. 3. Send loop-up code. This will cause the NIU to enter the normal loopback mode Override Mode When in the Override mode, LED will be lit and the unit will assume the transmission paths as shown in Figure 3. At this point, the test person can: 1. Take no action. When customer signal is restored or when the 60-minute timer expires, the NIU will return to idle. If the NIU enters the idle via timeout and the CPE signal is still absent, the NIU will revert to the selected /AIS/CDI mode. 2. Send loop-up code. This will cause the NIU to enter the normal loopback mode of operation Normal Loopback from Override Mode When in normal loopback, the 60-minute loopback timer is activated, the LED will be flashing, the LED will be lit steady and the unit assumes the transmission path as shown in Figure 4. At this point the test person can: 5

6 Section A Rev. D 1. Take no action. NIU will remain in loopback indefinitely if loopback timeout S4-1 is OFF, or return to idle mode after 60 minutes if S4-1 is enabled. If, after the 60-minute timer expires, the CPE signal is still absent the unit will revert to the /AIS/CDI mode. 2. Send loop-down code. This will return the NIU to idle. If the CPE signal is still absent the unit will revert to the /AIS/CDI mode Remote Query The NIU provides the ability to remotely query the NIU to determine the loss of signal mode of operation as optioned by S6. To query the NIU, the test person must first send the loop up code. While in loopback, the test person then sends the inband query code Response 1. If optioned to enter loopback upon a condition, the NIU will remain in loopback. 2. If optioned to send AIS upon a condition, the NIU will return AIS toward the network. 3. If optioned to send CDI upon a condition, the NIU will return CDI toward the network. The NIU will return the response for as long as it is receiving the query code. To exit the query state and return the NIU to normal mode, send loopdown code to the NIU Remote Toggle The NIU also provides the capability to remotely override and change the mode set by S6. When remotely changed, the NIU will continue to operate in this new mode even if power is lost. When the NIU has been remotely programmed to a different response other than that set by S6, the PWR LED will flash. To remotely override the mode set by S6: 1. Send the loop up code. 2. Next, send the inband query code continuously. The NIU responds with the present setting. 3. Remove the code for at least five seconds, then resend it. 4. The NIU will toggle to the next option. If this is not the desired response, repeat step 3 to toggle to the next option state. 5. Send loopdown code to the NIU. This will then lock the NIU to the new option state. 3.9 Power The NIU offers a flexible powering option which will allow the unit to operate directly from T1 metallic spans, or from a locally provided 22 to 56 Vdc source. When locally powered, the DC source can be negative or positive ground referenced. This allows the unit to operate from conventional -48 Vdc sources as well as +24 Vdc source found in certain wireless/pcs applications. The NIU provides a fuse on its power input lead, pin 35. This fuse prevents the failure of an individual NIU from affecting other units on the same local power supply. This fuse is not field replaceable. - NOTE - Set any/all manual option switches prior to installing the unit. 4. OPTIONS & FRONT PANEL FEATURES The NIU contains various features and switch options located on the front and side (PCB) panels, as shown and described in Figure 9, to condition the module for proper operation and for maintenance and testing purposes. 4.1 Front Panel Features Status LEDs The NIU contains four status LEDs. See Table 3 for a description of the front panel LEDs and Figure 9 for their locations. LED Label PWR LED Color LED State LED Description Green Off Power not applied to unit, P5 is optioned incorrectly for power source being used, or unit has failed, opening its internal power fuse. On Power is applied to unit. Flashing NIU is powered and mode is remotely toggled to a state different from that set via S6. Yellow Off NIU is idle or in normal operation (i.e., not in loopback). On NIU is in loopback and 60-minute timeout mode is disabled. Flashing NIU is in loopback and 60-minute timeout mode is enabled. Red On NIU detects a loss of signal from the network. Off NIU is receiving signal from the network. Red On NIU detects a loss of signal from the customer interface. Off NIU is receiving signal from the customer interface. Table 3. Front Panel LED Conditions and States Front Panel Push Button Switch A push button switch located on the front panel provides manual loopback activation/deactivation. The switch is labelled MAN " and is described and shown in Figure Bantam Jacks The NIU contains breaking-type access jacks on all ports and monitor jacks on the input ports. See Table 4 for a description of these six jacks Test Point Jacks The NIU also contains test point jacks on the front panel which allow a craftperson to measure span current. These signal-interrupting jacks are labelled TP1 and TP2, as listed in Table 4. 6

7 Rev. D Section A NIU IDLE START SEND LOOPUP CODE SEND 16-BIT BAND QUERY CODE CODE SENT FOR >5 SEC.? YES NO UNIT RESPONDS WITH PRESENT SETTG OF OPTION YES CODE ABSENT FOR >5 SEC.? NO IS THIS THE DESIRED RESPONSE? YES NO CHANGE OPTION TO NEXT CHOICE (/AIS/CDI)? NO YES STOP SENDG CODE YES NO CODE SENT FOR >5 SEC.? SEND LOOPDOWN CODE Figure 6. Query/Toggle Procedure LOOPUP CODE Override Mode LOOPDOWN 60 MUTE TIME or CPE PRESENT Idle Mode CPE LOS CPE PRESENT Mode, AIS, CDI LOOPUP CODE 60 MUTE TIME or LOOPDOWN CODE Normal Mode LOOPUP CODE Figure 7. Loopback/ Override Diagram 7

8 Section A Rev. D 34 Shield FROM FACILITY 7 13 T R TP1 SPAN CURRENT 10 OHMS TP2 LOCAL SPAN P5 PWR ( ) LOCAL POWER (+) POWER CONVERTER P5 LOCAL SPAN TO FACILITY T1 R1 /LPBK DISABLE ENABLE LOS CODE MAN S5 SYSTEM CONTROLER S4 S6-1 T.O. -2 RGN AIS CDI MODE K1 S1 S3 S LOOPBACK O S4-2 K1 DISABLE ENABLE K1 CDI/AIS GENERATOR NETWORK LOOPBACK CPE PATH LOOPBACK LOS CT1 5 CR1 15 TO FROM CPE CT CR MON SURGE PROTECTION SURGE PROTECTION P5 LOCAL SPAN 36 Shield 1 MON O 38 CPE 39 Figure Block Diagram 8

9 Rev. D Section A Jack Type Bantam Jacks Test Points Jack Name MON MON Description Monitors the signal from the network. Breaks signal from the network and provides access to port of NIU. Breaks signal from the network and provides access to port of NIU. Monitors the signal from the customer interface. Breaks signal from the customer interface and provides access to port of NIU. Breaks signal from the customer interface and provides access to port of NIU. Used for measuring span current. Voltage Span Curr measured across these points should be TP1, TP2 between 0.57 and 0.63 V which equates to 57 to 63 ma of span current. Table 4. Front Panel Test Jacks 4.2 PCB Option Switches (Side Panel) The NIU contains option switches and jumpers on the side-panel PCB to option the unit for proper operation. The location and description of each option is shown in Figure STALLATION Installation consists of inspecting the equipment for damages, following proper safety precautions, mounting the NIU in the proper slot of the mounting assembly, and verifying the presence of power and signalling as indicated by the status LEDs (see Table 3). - SPECTION NOTE - If not previously inspected at the time of delivery, visually inspect the unit for damages prior to installation. If the equipment has been damaged in transit, immediately report the extent of the damage to the transportation company and to Westell (see Part 6 for telephone number). - PRECAUTIONARY STATEMENT - Never install telephone wiring during a lightning storm. Never install telephone jacks in wet locations unless the jack is specifically designed for wet locations. Never touch uninsulated telephone wires or terminals unless the telephone line has been disconnected at the network interface. Use caution when installing or modifying telephone lines. This NIU should be installed behind devices that provide primary lightning protection. CAUTION - STATIC-SENSITIVE This product contains static-sensitive components! Proper electrostatic discharge procedures must be followed to maintain personal and equipment safety. Do not store units near magnetic, electromagnetic or electrostatic fields. Always store or ship units in the original static-protective packaging from Westell. Use anti-static mats when working on units. 5.1 Mounting the Module Before installing the NIU, please observe all safety notes and cautions and set all option switches to their desired positions (see Part 4). The NIU installs in a 200 MECHANICS or 400-type shelf or mounting assembly. Align the module with the mounting assembly card guides above and below the module and insert as far as it will go into the slot connector. - CAUTION - Use care when installing and removing modules - do not force a module into place. If a module resists insertion, remove it and check for obstructions in or near the connector and mounting slot, then carefully re-align and re-insert the unit. Function Designation Pin Number T 7 R 13 CT1 5 CR1 15 CT 55 CR 49 T1 41 R1 47 Shield 34/38 Shield1 36/39 POWER (-) Local Power 35 (+) Local Power 17 Table 5. Pin/Lead Designations 5.2 Making Installer Connections The unit makes electrical connection to external equipment through a 56-pin, wire-wrap card-edge connector in the mounting assembly. Pin connections (pin-outs) are listed Table TESTG & TROUBLESHOOTG 6.1 Testing After installation is complete, initial testing consists of following the steps in Table 6. This equipment should not be field repaired. If the equipment is suspected of being faulty, replace it with another unit, optioned identically, and retest. If the replacement unit appears to operate correctly, the original unit may be faulty and should be returned to Westell for repair or replacement (Paragraph 8.2). 6.2 Troubleshooting If trouble is encountered, verify all installer connections to the assembly and check that the CO power fuse is not blown. Also verify all module connections and option switch settings, and verify the modules are making a positive connection with the shelf connector. If trouble persists, replace the suspect unit and repeat procedures outlined. These procedures are not designed to effect repairs or modifications. Any tests beyond those outlined herein, or repairs made beyond replacing a faulty unit, are not recommended and may void the warranty. 9

10 Section A Rev. D DS1 NIU O UT M O M I N PWR S2 O ENABLE SIG LMTR S SPAN LOC P MAN TP1 TP2 I N M O M S5 RGN DISABLE S1 ENABLE RGN TO AIS CDI S6 MODE O UT S Option Position Description P5 Jumper ENABLE Regenerates the DS1 signal from the customer interface to the network. S1 NOTE: When this option is selected, ensure S3 (Signal Limiter) is set to 0. Regen DISABLE Transparently passes the DS1 signal from the customer interface to the network. 0, 0 Set both segments up (away from values shown) to obtain 0dB of loss in the loopback path. S2 (2 section) O S3 Signal Limiter S4-1 T.O. S4-2 ENABLE Regenerates the DS1 signal from the network to the customer interface. Regen DISABLE Transparently passes the DS1 signal from the network to the customer interface. S5 MAN S6 Mode SPAN LOC 0, , 0 7.5, Configures the unit to operate from the T1 facility span power. Configures the unit to operate from a local 22 to 56V power supply. 15 Limits signal from customer interface to network to approx. 0.7 V peak. ENABLE Enables 60-minute Loopback timeout feature for code-activated loopback. A flashing LED indicates T.O. timer is activated. DISABLE Disables 60-minute Loopback timeout feature; Loopback can still be activated but with no the time out. PUSH/ PUSH AIS CDI A Set left segment up (away from value shown) and right segment down (toward value shown) to obtain 7.5dB of loss in the loopback path. Set left segment down (toward value shown) and right segment up (away from value shown) to obtain 15dB of loss in the loopback path. Set both segments down (toward values shown) to obtain 22.5dB of loss in the loopback path. Does not limit signal from customer interface to network. Limits signal from customer interface to network to approx. 1.3 V peak. Push once to activate loopback manually. Press a second time to deactivate loopback. Configures unit to enter Loopback upon detecting loss of signal from customer interface. Configures unit to send AIS code toward network upon detecting loss of signal from customer interface. Configures unit to send CDI code toward network upon detecting loss of signal from customer interface. Figure Front Panel and Switch Options 10

11 Rev. D Section A STEP PROCEDURE CORRECT RESULT Option and install unit Ensure connections to the DS1 are made properly, and the connections to the customer network interface are disconnected Inject a QRSS signal into unit locally via jack at the level specified on the CLR/WORD document. If no level is specified, use -15 db PWR LED and LED should be ON. If optioned for -, the LED will also be ON. LED may be ON or OFF depending on the status of any signal from the network LED should be OFF IF CORRECT RESULT IS NOT OBTAED If span powered, verify P5 is set to SPAN. Place a voltmeter across the & pairs and verify reading of approx. 15 V 4 Measure the signal at the jack with a terminated test set If (S4-2) is Disabled, signal should be same as injected signal +0 to -1 db If (S4-2) is Enabled, signal should be 0dBdsx 1.5 db 5 Press the front panel MAN switch Verify LED is ON steady 6 Press the front panel MAN switch Verify LED is OFF 7 Change the signal at the jack to loop up code for at least 5 seconds, then return to QRSS Verify LED is ON steady or flashing (dependent on the setting of S4-1, T.O.) 8 Move test set receiver from jack to the jack and measure the level Signal should be the level that was set via O switch S2 (ex: If S2 is set for 15 db, the level measured should be -15dB 1.5 db) 9 Change signal at jack to loop down code for at least 5 seconds, then return to QRSS Verify LED is OFF 10 Inject a QRSS signal into unit locally via jack at the level specified on the CLR/WORD document. If no level is specified, use -15 db LED should be OFF 11 Measure signal at jack with a terminated test set If (S1) is Disabled, signal should be same as injected signal +0 to -1 db If (S1) is Enabled, signal should be 0dBdsx 1.5 db Be sure Signal Limiter is set to 0. Otherwise, NIU may be faulty. Replace and retest LED should be ON If Mode (S6) is set for, verify LED is ON steady 12 Change QRSS signal at jack to -30 db If Mode (S6) is set for AIS, verify test set sees AIS code at the jack If Mode (S6) is set for CDI, verify test set sees CDI code with SF framing at the jack NOTE: The procedures above tests the functionality of the NIU only. Please follow local Methods & Procedures to ensure span integrity. The above procedures can be done locally to verify operation of the NIU. These procedures do not verify the integrity of the T1 facility and does not require coordination with the remote test center. Table 6. Test Procedures 7. CUSTOMER & TECHNICAL SERVICES 7.1 Customer Service & Technical Assistance If technical or customer assistance is required, contact Westell by calling or using one of the following options: Voice: (800) global_support@westell.com For additional information about Westell, visit the Westell World Wide Web site at 11

12 Section A Rev. D 7.2 Part Numbers This equipment is identified by a model number and issue letter imprinted on the front panel (A ). Each time a change is made to the product which changes the form, fit or function of the product, the issue letter, indicated by the prefix letter of the assembly number (A90), is advanced. Be sure to indicate the issue level and model number when making inquiries about the equipment. 8. WARRANTY & REPAIRS 8.1 Warranty Westell warrants this product to be free of defects at the time of shipment. Westell also warrants this product to be fully functional for the time period specified by the terms and conditions governing the sale of the product. Any attempt to repair or modify the equipment by anyone other than an authorized Westell representative will void the warranty. 8.2 Repair and Return Westell will repair or replace any defective Westell equipment without cost during the warranty period if the unit is defective for any reason other than abuse, improper use, or improper installation. To return defective equipment, first request a Return Material Authorization (RMA) number from Westell by calling or using one of the options shown below. Once an RMA number is obtained, return the defective unit (freight prepaid), along with a brief problem description, to the address we will provide to you when you contact us. Voice: (630) rgmdept@westell.com Replacements will be shipped in the fastest manner consistent with the urgency of the situation. Westell will continue to repair or replace faulty equipment beyond the warranty period for a nominal charge. Contact Westell for details. 9. SPECIFICATIONS 9.1 Regulatory/Agency Specifications The NIU is designed to meet the following regulatory and environmental specifications or requirements: UL 1459 Recognized Component Lightning and Power Cross: Meets requirements of Bellcore GR-1089 CORE FCC Part 15 (emissions and susceptibility) TR-TSY Ordering Specifications To order units, call the telephone numbers shown in Paragraph 7.1 and please specify a specific model number shown in Table 7. Model # Part # Description A DS1 Network Interface Unit.. CLEI* Code: T1SMM055AA. Barcode/ECI: CPR: J *CLEI is a trademark of Telcordia Technologies. Table 7. Ordering and Option Information 9.3 Electrical and Physical Specifications The electrical and signalling specifications are listed below, and the physical specifications are shown in Table 8. Physical Feature U.S. Metric Height 5.6 in cm Width 0.7 in. 1.8 cm Depth 6.0 in cm Weight (approx.) 6 oz g Operating Temp. -40 to 149 F -40 to 65 C Humidity Mounting 0 to 95% (non-condensing) Mounts in any 200 MECHANICS or 400-type mechanics mounting or shelf. Table 8. Physical Specifications Transmission A. Channel Insertion Loss ( OFF): 1.5 db, max. B. or Channel Regeneration Range: -31 to 0 dbdsx C. Port Impedance: 100 Ohms (±22 %) at 772 khz Detectors D. Receive Loss Of Signal Detector () Threshold: 175 (±75) consecutive zeros -31 dbm dsx E. Transmit Loss of Signal Detector () Threshold: 175 (±75) consecutive zeros -24 dbm dsx F. Loopback Activation Codes: Inband (unframed, SF framed): (>5 sec.) ESF: (right-most bit first) G. Loopback Deactivation Codes: Inband (unframed, SF framed): (>5 sec.) ESF: (right-most bit first) H. Loopback Timeout Disable Codes: Inband: (>5 sec.) ESF: (right-most bit first) ESF: (right-most bit first) I. Code Detector Range: -31 to 0 dbdsx J. Code Detector Maximum Error Rate: 10-3 Power K. Span Power Voltage Drop: 15 V nominal at 60 ma L. Span Power Operating Current Range: 57 to 63 ma M. Local Power: 22 to 56 Vdc, ± reference to ground N. Local Power Current Consumption: 66 ma, max. O. Heat Release: 3.5 Watts, max. 12