General Description & InstallationPractice 030-100058 ev. F Loop Signaling epeater Model 4370-00 Section 4370-00-100 Issue B Westell, Inc. September 1999 All ights eserved Contents 1. General page 1 2. Operating Description page 1 3. Inspection and Warranty page 2 4. Installation page 3 5. Options page 3 6. Application Notes page 5 7. Testing page 5 8. Specifications page 5 4370-00 T CO 1. General STA 1.01 The Westell 4370-00, Loop Signaling epeater, is a 400-type plug-in module that is used in the Westell 43MA System of Station Packages to provide range extension of loop signaling. The 4370-00 is well suited for provision of Off-Premises Station interconnection at the PBX site in accordance with FCC requirements of Part 68 and satisfies all requirements of Part 68 on the CO/PBX connection side. 1.02 This document is revised to ev. F to reflect the new logo, and new address for Westell. 1.03 Features of the 4370-00 are as follows: Selectable impedance settings of or Ohms Current limiting on the station side loop Compatible with Western Electric HOIZON Systems (ringing can be detected either across Tip and ing or on a separate pair of leads) Full pulse corrector Selectable option for forward disconnect Selection of either bypassed or repeated ringing Switch option for sending standard 2-second ON/4-second OFF ringing Machine Start lead for control of ringing source Operates from a local power source of 48Vdc Terminates a 2-wire facility at the customer s premises Provides for the interconnection of equipment via the following, standard facility interface codes: OL13A OL13B OL13C Provides front-panel-accessible test points for Tip and ing on both the Station and Office sides of the unit Provides a front-panel LED to indicate Busy conditions BUSY B90-437000 2. Operating Description 2.01 efer to Figure 3, the 4370-00 Block Diagram, as needed, while reading the following description of operation. Voice Path 2.02 The voice path is provided on the 4370-00 through a toll-grade transformer repeat coil.. The transformer allows voice signals to pass through the unit in both directions with very little loss, while allowing access to the signaling currents i both directions for supervisory functions. The audio impedance on each side can be optioned for either or Ohms independently. Battery Feed 2.03 The battery feed circuit provides talk battery to the station end. The circuit is a balanced resistive source of approximately 200 Ohms on each side of the line. The station end can be given internal talk battery of 48Vdc, or an external boosted battery of up to 96V DC may be used. When using the internal talk battery, the 4370-00 will provide 23mA of loop current into a 1500-ohm loop at 48Vdc. The loop current is limited to approximately 140mA DC via the Current Limiter circuit. Loop Detector 2.04 The Loop Detector circuit detects the on-hook/ off-hook status of the station equipment. The circuit re- CLEI is a trademark of Bell Communications esearch, Inc. Printed in USA page 1 of 8
Section 4370-00-100 sponds to metallic currents but ignores longitudinal currents to provide for proper signaling operation in the presence of high ac induction. The circuit detects on-hook, offhook, hookswitch flash, dial pulses and off-hook during ringing (ring trip) from the station equipment. Dial Pulse Corrector 2.05 The output of the Loop Detector feeds a circuit used for the correction of dial pulses. The pulse corrector detects dial pulses and corrects any percent break from 35 to 85% at 10 PPS to 58% breakout. ing Trip 2.06 Upon detection of a station off-hook condition, the 4370-00 will remove ringing from the station side and provide a loop closure to the office side. Loop Closure Circuit 2.07 When the station end is off hook, the 4370-00 provides a loop closure to the PBX/CO. The loop closure provides a DC path to the office of either 200 Ohms or Ohms (approximately), switch selectable. The DC path is removed when the station is on hook. When off hook, the voltage drop across the office side of the unit, has a DC V-1 characteristic similar to a 500-type telephone set. See Figure 1. This allows for good transmission quality when a parallel instrument is used on the office side. The office side interface meets the requirement of FCC Part 68. VOLTAGE (VOLTS DC) 12 10 8 6 4 2 0 4370 OFFICE SIDE (LD CLOSED) 20 40 60 80 CUENT (ma DC) Figure 1. 4370-00 vs 500-Tel Set DC TYPICAL 500-TYPE TELEPHONE SET ing Detector 2.08 The ing Detector circuit detects ac signals in the ringing frequency range between 40 and 150 Volts MS. The circuit is designed such that the EN (inger Equivalency Number) is 1dB to the PBX/CO. The ing Detector appears across the Tip and ing normally, but can be placed across a separate pair of wires by placing switch S3 in the D position. This allows the ing Detector to be used in conjunction with Western Electric HOIZON systems equipped to ring on a separate station pairs. ing Timer/Control 2.09 The output of the ing Detector is routed to the ing Timer circuit. This circuit controls the application of ringing voltage to the station equipment via the ing elay, K2. Office-side ringing can be bypassed or repeated toward the station. When in the bypassed (BYP) position, ringing, generated by the switching equipment, is passed through the unit to the station equipment unchanged. Since ringing voltage is supplied to the station from the switching equipment instead of a local ring generator, the switching equipment s ring-trip range will come into play. If the ring-trip range of the switching equipment and the 4370-00 differ, the lesser of the two ranges will determine the maximum line length. 2.10 When in the epeated inging mode (PT and BG), ringing from the switching equipment is regenerated by a ing Generated at the same location as the 4370-00 unit. When in the PT mode, the bias voltage on the ringing is determined by the difference in DC potential between the Superimposed inging Generator (SG) lead and ing Generator eturn (G) lead. When in the GB mode, bias will be determined by the difference in the DC potential between the SG lead and module ground. Note: For proper bias, the SG lead must be negative in potential with respect to the G, GND, or +TB leads. ing generator bias can be 48, 72 or 96Vdc. 2.11 When optioned for the GB or PT modes, the 4370-00 can supply two types of ringing. If S6 is set in the T position, the unit will follow the ringing cycle supplied by the office end and repeat this cycle to the station end. When S6 is set to the 2/4 position, the ringing cycle of 2-seconds ON/4-seconds OFF will be supplied to the station end. The 4370-00 will detect and/or follow ringing bursts of 100ms or longer. Note: If continuous ringing remains present on the office side for more than 9 seconds, relay K2 will release and will stay released until ringing is removed for 100ms and then re-applied. Forward Disconnect Detector/Timer 2.12 If the called party returns on hook and the calling party (4370-00 station side) remains off hook, the CO/ PBX may initiate a forced disconnect by removing talk battery to the station when a disconnect is detected on the office side. Detection and release times are about 40msec in duration. This feature may be disabled by setting the switch to the OFF position. Note: Since the 4370-00 cannot be accessed during a forced disconnect, the front-panel BSY (busy) LED will stay lit. Power Supply 2.13 The 4370-00 contains a power supply which produces all internal voltages required when supplied with 48Vdc. The unit requires 60mA of DC supply current maximum, plus talk battery current (limited to 140mA DC, 40mA DC at 800-ohm loop) when the internal talk battery option is used. 3. Inspection and Warranty Inspection 3.01 Upon receipt of the equipment, inspect the equipment thoroughly. If the equipment has been damaged in transit, please report the damage to the transportation company and to Westell. page 2
Warranty 3.02 Westell warrants this product to be free of defects at the time of shipment. Westell warrants this product to be functional for the time period specified by the terms and conditions governing the sale of the product. 3.03 This equipment should not be field repaired. Any attempt to repair or modify the equipment by anyone other than an authorized Westell representative will cause the warranty to be void. If the equipment is suspected of being faulty, replace it with another unit. If the replacement equipment operates correctly, the original unit may be faulty. In this case, return the faulty unit to Westell for repair or replacement. epair and eturn 3.04 Before returning equipment, a eturn Material Authorization (MA) number must first be requested from Westell. In an effort to better serve you, please include a brief description of the problem, then return the equipment to: Westell, Inc. 750 N. Commons Drive Aurora, IL 60504 ATTN:.G.M. Department 3.05 Westell will repair or replace any defective Westell equipment without cost during the warranty period if the unit is found to be defective for any reason other than abuse, improper use or improper installation. If a replacement unit is required, it will be shipped in the fastest manner consistent with the urgency of the situation. 3.06 Westell will continue to repair or replace faulty equipment beyond the warranty period for a nominal charge. Contact Westell or your local Westell Sales epresentative for details. Technical Assistance 3.07 If technical assistance is required, contact the Westell Technical Service Department by calling: Westell, Inc. (630) 898-2500 1-800-323-6883 or FAX: (630) 375-4931 or e-mail: global_support@westell.com 3.08 This equipment is identified by a model number and issue letter (example: B90-437000). 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 (B90), is advanced. Be sure to indicate the issue level along with the model number of the product when making inquiries about the equipment. CAUTION STATIC SENSITIVE Section 4370-00-100, Issue B This equipment contains static sensitive components. Be sure proper electrostatic discharge procedures are followed before handling/installing the equipment. Safety Notes (1) Never install telephone wiring during a lightning storm. (2) Never install telephone jacks in wet locations unless the jack is specifically designed for wet locations. (3) Never touch uninsulated telephone wires or terminals unless the telephone line has been disconnected at the network interface. (4) Use caution when installing or modifying telephone lines. (5) When installed, this unit is intended to be used behind devices that provide primary lightning protection. Installer Connections 4.02 When making shelf connections, Westell recommends using 22 gauge, or heavier wire, for power ( 48V, pin 35), Ground (pin 17), +TB pin 32), TB (pin 33) and SG (superimposed ringing, pin 46. Also, before applying power to the unit, be sure the unit is properly optioned per Section 5. T D1 D2 +TB TB G SG Table 1. 4370-00 Pin-out Assignments Lead Designation Office Side Station Side Separated inging Pair External Talk Battery ing Generator eturn Superimposed ing Generator Input Pin Number 55 49 41 47 5 15 32 33 12 46 MS Machine Start Output 30 48Vdc Power Input 35 GND Ground 17 4. Installation 4.01 The 4370-00 installs in a 400-type shelf and makes electrical connections to external equipment through a 56-pin wire-wrap-type card-edge connector of the mounting assembly. Pin outs used by the 4370-00 are listed in Table 1. Before installing the unit, however, please observe the following safety notes. 5. Options 5.01 The 4370-00 is equipped with option switches that are used to configure the unit for proper operation for a given application. Figure 2 shows the approximate location of these option switches. page 3
Section 4370-00-100 4370-00 S4 S1 ON S2 LD OFF ON T S7 BYP EXT CO STA OFF S8 PT T S6 GB S5 INT S3 D 2/4 NOM BUSY B90-437000 Figure 2. 4370-00 Option Location Office Side / Station Side Line Impedance (S1/S4) 5.02 Option switch S1 and S4 selects the impedance for the Office Side and Station Side, respectively, to either Ohms or Ohms. Office Loop Closure esistance (S2) 5.03 Set switch S2 (LD) to ON to provide a loop closure resistance of approximately 200 Ohms to the office side of the unit. When set to Off, a loop closure resistance of approximately Ohms is applied to the office side of the unit. Switch S2 should be ON for OL13A interfaces and should be OFF for OL13B and OL13C interfaces. ing Detection (S3) 5.04 Set switch S3 (D/NOM) to NOM to detect ring voltage on the office side Tip and ing pairs. Set S3 to D to detect ringing voltage on a separate pair. The wires for the separate pair with the ringing signal are brought to pins 5 and 15 of the 4370-00. INT/EXT Talk Battery (S5) 5.05 Set switch S5 (INT/EXT) to INT to provide 48-volt talk battery to the station set via the internal power source of the unit. Set switch S5 to EXT to provide talk battery to the station from an external voltage source connected to the unit via pin 32 (+TB) and pin 33 ( TB). Talk battery may be up to 96Vdc. ing Follow or 2-Sec. ON/4-Sec. OFF (S6) 5.06 Set switch S6 to T to ring the station with the same ring sequence as that received from the CO/PBX. In the T position, the unit repeats distinctive ringing. Set S6 in the 2/4 position to ring the station with a 2-second ON, 4-second OFF cycle, regardless of ring cycle received from the office end. Note: in order to use the ing Follow or 2/4 options, switch S8 must be set to either the PT or GB mode. Forward Disconnect (S7) 5.07 Set S7 to ON to enable the forward disconnect circuit. Set S7 to OFF to disable the forward disconnect feature. Forward Disconnect (S8) 5.08 Switch S8 selects either bypassed or repeated ringing. For bypassed ringing, set S8 to BYP (bypass); no connections to a local ring generator are needed in this mode. For repeated ringing with ring-generated bias determined by the difference in dc potential between SG and G, set S8 to PT (repeated). For repeated ringing with ring-generated bias determined by the difference in dc potential between SG and GND or +TB, set S8 to GB. 5.09 To option the unit for a particular standard facility code, use Table 2. Standard Facility Code Table 2. Standard Facility Codes S1 S2 S3 S4, S5, S6 S7 OL13A ON NOM AS EQUIED OL13B OFF NOM AS EQUIED OL13C OFF NOM AS EQUIED page 4
6. Application Notes 7. Testing Section 4370-00-100, Issue B Talk Battery/Loop Current equirements 6.01 equirements for the talk battery voltage on a given station loop are generally set by the minimum loop current requirement of the station equipment. The unit will work with station loops up to 3000 Ohms with a 48-volt battery, up to 4500 Ohms with a 72-volt battery, or up to 0 Ohms with a 96-volt battery. The requirement of 23mA DC for DTMF-type instruments, however, reduces these ranges to 1550, 2570 and 3 Ohms, respectively. Where less than 23mA DC of loop current is acceptable, these ranges may be increased accordingly. The limitations on the talk battery supplied to the unit are as follows: +TB must be positive relative to TB. The total voltage difference between +TB and TB must not exceed 110 Volts. +TB must not be greater than +110Vdc relative to earth ground. TB must not exceed 110Vdc relative to earth ground. Noise on the +TB, TB source should not exceed 30dBrnC. TB must be negative with respect to the unit. ing Trip / ing Generator Input 6.02 The ring generator is connected to the unit via pin 46 and must have a dc bias which is negative relative to the dc voltage supplied to the Tip side of the station line. Generally, the ring generator should be superimposed upon 48Vdc. Superimposed ringing with 48-volt bias will give the unit a ring trip range of 3000 Ohms when the +TB lead is ground, 4500 Ohms when the +TB lead is +24Vdc, or 0 Ohms when the +TB lead is +48Vdc. Since the ring trip range is at least 3000 Ohms in every case when 48-volt biased ring generated is used, it is normally not necessary to use a ring generator biased to a battery that is boosted above 48 Volts, even if 96-volt talk battery is employed for purposes of maintaining loop currents above 20mA DC in the talking condition. Mounting in a Westell 43MA Mounting Package 6.03 This unit is intended to be install into a standard Westell 43MA-Series Mounting Package. The ringing source may then be provided via the Westell 4320-00 ing Generator plugged into the appropriate card slot of the 43MA-type mounting. Place the 4320-00 bias switch (S2) in the BC position and open the enable option, S4. No additional wiring is required. One 4320-00 can provide the ringing source for many 4370-00 modules. The 4320-00 can ring at least 10 telephones simultaneously. Boost battery can be provided by using the 4330-00 Boost Battery module in any 43MA cad slot. The 4330-00 will provide boosted talk battery for at least 10 circuits, dependent on the loop lengths. Set switch S5 on all 4370-00 units requiring boosted battery in the EXT position. Option the 4330-00 for the desired battery voltages. Only one 4330-00 may be used per mounting package. Again, no additional wiring is required. 7.01 Testing may be done by connecting a telephone across Tip and ing on the station side with Tip and ing on the office side connected to the CO or PBX. By putting the telephone in its off-hook state, dial tone from the CO/ PBX should be heard. The telephone can be dialed and the call should complete to verify proper operation of the unit. The telephone should then be called from another station to verify proper ringing operation. Completion of the call indicates proper unit functions. 7.02 If trouble is encountered with the unit, verify that all installer connections are properly made, the unit is properly optioned and that the proper voltages and ground are present at pins 35 and 17, respectively. Make certain that the module is fully inserted in the shelf and is making good contact with the backplane connector of the mounting assembly. Unplug and re-insert the module if necessary. If trouble persists, replace the unit with another unit, optioned identically, and re-test. If the problem disappears, the original unit may be faulty and should be returned to Westell for repair. 8. Specifications Transmission Station / Office Side Impedance: Ohms or Ohms +2.15F, selectable via S1 and S4 Crosstalk Attenuation: 80dB minimum from 300Hz to 3000Hz Frequency esponse: 1dB max, relative to 1000Hz, from 300Hz to 4000Hz eturn Loss: 20dB EL minimum vs Ohms or Ohms +2.15F Longitudinal Balance: 60dB minimum from 400 to 4000Hz Insertion Loss: 1dB maximum at 1000Hz Transmit Loss: 0.5dBm insertion loss (typical) Signaling Maximum Loop Signaling Limits: 3000 Ohms, 48 Volts 4500 Ohms, 72 Volts 0 Ohms, 96 Volts Station-side Loop Limits vs Current: Loop 48V 72V 96V Current 16mA 2400 3 5400 21mA 1750 2850 3950 23mA 1550 2550 3 Maximum Station-side Loop Current: Limited to 140mA DC max. Maximum Station-side Cable Leak: 10,000 Ohms Station-side Loop Current: Detection: 50ms (10ms) elease: 59ms (7ms) Forward Disconnect: Detection: 45ms (7ms) page 5
Section 4370-00-100 elease: 40ms (6ms) Pulse Correction: Input Percent Percent ate Break In Break In 8PPS 30 to 85 57 (2) 10PPS 30 to 85 58 (2) 12.5PPS 40 to 80 59 (2) ing Generator Detection: 100ms, maximum ing Trip ange: 3000 Ohms, 48V bias (G eturn rel. to +TB) 4500 Ohms, 72V bias 0 Ohms, 96V bias Signaling Immunity to Longitudinal Induction: 60V MS AC Office-side Loop Closure esistance: 200 Ohms, max., LD ON Ohms, max., LD OFF Office-side inging Detection ange: 40 to 150V MS from15.3 to 68Hz ing Supply equirement: 80 to 150V MS from15.3 to 68Hz (negative superimposed, battery connected) General Input Voltage: 44 to 56Vdc Input Current: Idle: 20mA, maximum Busy: 60mA, maximum Operating Temperature: 0 to 50C; Humidity, 0 to 95% no condensation Dimensions: 5.6 x 6.0 x 1.5 Weight: Approx.: 17 oz. Mounting: Westell 43MA-xx (400-type) shelf via 56-pin card-edge connector page 6
Section 4370-00-100, Issue B 12 G STATION SIDE 41 32 +TB EXT S5-2 SEE NOTE 4 CUENT LIMITE INT 33 K2 T 55 D NOM TB 5 49 EXT 47 17 46 D1 T LC K1 X ING SENSO INT D CUENT LIMITE X X SEE NOTE 3 LD NOM CUENT SENSO 15 D2 ING TIP DETECTO ING ELAY CONTOL DETECT DELAY SG SEE NOTE 5 30 MS SEE NOTE 6 X OFFICE SIDE LOOP CLOSUE ELAY CONTOL PULSE COECTO LC S3-2 S4-1 200 2W DOP TO TE VIA J11C, ETC. K3 S3-1 K3 S2 K1 BUSY 8. STATION SIDE LOOP LENGTH LIMITS: 23mA INSTUMENT CUENT LIMIT SIGNALING LIMIT TALK BATTEY 48V 1550 OHMS 3000 OHMS K2 OFF HOOK / DIAL PULSE DETECTO DIAL PULSE TIME ING TIME 2- / 4- SEC TIME CONTOL 2570 OHMS 4000 OHMS BYP PT GB T 2 / 4 LOOP CUENT DETECTO (FOM CUENT SENSO) 40MSEC DELAY K2 FOWAD DISCONNECT CONTOL K3 48V 72V 3 OHMS PT GB BYP ING DETECTO (FOM ING SENSO) 1. DENOTES FONT-PANEL TEST POINTS BATT 48V 35 48V GND POWE SUPPLY 48V 2. MAXIMUM AUDIO LEVEL: +10dBm 3. S2 ON FO OL13A 4. MAXIMUM TALK BATTEY: 56VDC 5. ING GENEATO MUST BE BIASED NEGATIVE ELATIVE TO +TB FO ING TIP S8-1 0 OHMS 96V S8-2 200 6. TO 4320-OO, PIN 30 7. S7 ON TO PASS FOCED DISCONNECT FOM PBX/CO S6 S7 S4-2 44 TO 56VDC (110mA DC MAXIMUM) S1-2 S1-1 S5-1 Figure 3. 4370-00 Block Diagram page 7
Section 4370-00-100 Option Instructions 4370-00 Issue B S4 S1 ON S2 S1 S2 Options: Switching Side Impedance Set for Ohms or as required Local Drop esistor (LD) OL13A closed (ON) (less than 200 Ohms) OL13B open (OFF) OL13C open (OFF) ON S7 OFF S6 S8 PT BYP EXT INT T GB 2/4 S5 S3 LD OFF D NOM S3 S4 S5 S6 inging Detector Set to NOM except when detecting ringing on pins 5 and 15 Station Side Impedance Set as required for or Ohms Talk Battery Source Set for INT except when boosted, external talk battery source is needed (see practice) ing Timing Set for T to follow incoming ringing and pass distinctive ringing Set for 2/4 for 2-seconds ON/4-seconds OFF output and translate distinctive ringing S7 Forward Disconnect To repeat forward disconnect (battery removal), set to ON To ignore disconnects, set to OFF S8 inging Mode Set to BYP to bypass PBX/CO ringing Set to PT for local ing Gen biased between SG and G leads Set to BG for local ring Gen biased between SG and module ground page 8