ATP-4 600/900 OHM DC BYPASS UNIT, AND ATP-5 BYPASS TEST UNIT

Transcription

1 BELLSYSTEM PRACTCES SECTON AT&TCe Skmdad ssue, August 198! w J9933BA, BB, AND BC WRE TRANSMSSON UNTS, ATP 600/900 OHM DC BYPASS UNT, AND ATP5 BYPASS TEST UNT DESCRPTON f METALLC FACLTY TERMNAL CONTENTS PAGE GENERAL 1 () To add descriptive information on the ATP 600/900 Ohm dc Bypass Unit and ATP5 Bypass Test Unit TWOWRE TRANSMSSON UNT (J9933BA) 3 BYPASS TRANSMSSON UNT (J9933BB) TWOWRE TRANSMSSON UNT (J9933BC) 1 TWOWRE TRANSMSSON UNT (J9933BA) 01 The J9933BA wire transmission unit (Fig 1) is now rated manufacture discontinued t was designed to allow signaling lead access for the loop signaling repeater (LSR) and loop signaling extender (LSE) Fully modified J9933BA units include most features of the replacement unit J9933BC 5 ATP 6 ATP5 600/900 OHM DC BYPASS UNT BYPASS TEST UNT 7 MANTENANCE 8 REFERENCES 1 GENERAL 101 This section describes three nongain wire transmission units (J9933BA, BB, and BC) for the Metallic Facility Terminal (MFT) These units are used in the transmission unit slots of doublemodule MFT mounting shelves (J9933A) to provide access to the dc signaling path for the associated MFT signaling unit This section also describes the ATP and ATP5 units, which are used for special applications 10 The reasons for reissuing this section are listed below Revision arrows are used to emphasize the more significant changes The Equipment Test List is not affected (1) To change the section title 0 The J9933BA is a passive transformercoupled device with selectable input and output impedances (600 or 900 ohms) A capacitor in series with the transformer windings provides access to the A and B leads on both sides of the unit Figure is a schematic diagram of the J9933BA The Aside impedance is selected by a slide switch on the front panel (SWG Z) while the Bside impedance switch is designated STA Z Buildout resistance (BOR) is available to limit the current in the signaling path A switch designated SWG BOR is for the Aside A and B leads, and a switch designated STA BOR controls the Bside A and B leads A switch on the front panel designated NOR/REV controls the connection of the TR (Aside) and TR1 (Bside) leads to the transformer windings n the normal mode, the TR leads are connected to the Aside of the transformer and the associated A and B leads connect to the A side of the signaling unit n the reverse mode, the TR1 leads are connected to the Aside of the transformer and the associated A and B leads are connected to the Aside of the signaling unit This results in reversing the signaling leads to the signaling unit 03 When the J9933BA is used in a central office to interface a wire switch, impedances of 900 NOTCE Not for use or disclosure outside the Rell System except under written agreement Printed in USA Page 1

2 SECTON available to limit the signaling current in short loops A switch (NOR/REV) mounted on the printed wiring _, board allows interchange of A and B signaling unit leads with the A or B side of the transmission unit Figure is the schematic diagram of the bypass transmission unit TWOWRE TRANSMSSON UNT (J9933BC) o1 The J9933BC wire transmission unit (Fig 5), CPS7 of SD1 C35901, replaces the J9933BA unit The function is the same as the J9933BA unit, and modifications to improve compatibility have been made The buildout resistors have been removed since their function is now pro _ vialed by the associated signaling units 0 Other features of the J9933BC unit include the following ncreased ringing range when the LSR uses a common ringing source (ringing and regenerated ringing are in phase) Compatibility with groundstart circuits (16 F midpoint capacitors) Fig 1 TwoWire Transmission Unit J9933BA ohms should be selected for both sides f located at a 600ohm PBX, the side facing the PBX should be set to 600 ohms impedance and the facility side set to 900 ohms 3 BYPASS TRANSMSSON UNT (J9933BB) Provision of itched Maintenance Access _ System (SMAS) access connections Access to AS1 and AS leads mproved echo return loss (ERL) Shorting switches on SX inductors Reversing switch in signaling leads instead of reversing transformer connections 301 The J9933BB bypass transmission unit (Fig 3), CPS3 of SD1C35901, is designed to allow MFT signaling units to be used with V or V equipment 30 The J9933BB unit is connected to the SX or A and B leads of the V or V equipment and connects these leads to the associated MFT signaling unit Transmission characteristics are controlled by the V equipment since the bypass transmission unit is in the signaling path only 303 Buildout resistors for both the switching (SWG BOR) and station (STA BOR) sides are All switches mounted on the printed wiring board to prevent accidental operation o3 The schematic diagram of the J9933BC wire transmission unit is shown in Fig 6 The operation of screw switch S31 causes an improvement in the ERL measured through the unit by inserting resistor R1 The insertion of R1 increases the lkhz loss measured through the unit by 0 db n applications which do not have a return loss requirement, the switch may be opened to reduce the loss of the unit as shown in Table A Table A also shows the electrical characteristics of both the J9933BA and J9933BC units Page

3 1SS, SECTON / T SUG \ R / _ T STA \ 1 T 5 R T61,1 SWG z S(SW) () 16 RV 15 d=s 1, 9 3, m,10 5,,, F== L 6 R V R i A RV3 l; R 6 1 L 6 R3 s 3 10, STA BOR 5 S3(SW) i, SWG BOR 61 S(SW) la m% 7 1* R GRD FR CONN NOTE : NoR/REv SW rch S s5 Fig Schematic of J9933BA Wire Transmission Unit

4 SECTON $ATP 600/900 OHM DC BYPASS UNT 501 The ATP unit (Fig 7) provides wire passive transmission and 600/900ohm impedance selection for both the A and B sides of the unit This unit is electrically similar to the J9933BC unit except that the ATP provides dc bypass (or through) signaling Signaling lead access is not provided This unit provides a 600ohm equipment to 900ohm equipment impedance match where less than 1 db of wiring loss separates the two interfaces Specifically, a 600ohm PBX can be matchedtoa SLC* 96 Subscriber Loop Carrier System or D 900ohm channel unit where the SLC 96 subscriber loop carrier system or D terminal is on customer premises 8 REFERENCES 801 The following references will provide addi tional information REFERENCE TTLE General Description of MFT MFT Test Extender (J9933TB), Description and Operation General Application nformation for MFT 50 The controls for this unit are as follows (a) ASide Z and BSide Z: 600 or 900ohm impedance selections are made by slide switches on the component board designated A side Z and Bside Z SD1 C35901 CD1 C35901 Metallic Facility Terminal Circuit Common Systems Metallic Facility Terminal Circuit (b) NOR/MN LOSS: A switch designated NOR/MN LOSS is provided to change the loss characteristics of the unit When the switch is in the NOR position, the return loss of the unit is optimized with a small increase in insertion loss When in the MN LOSS position, the insertion loss is minimized with a reduction in return loss See Table A for the J9933BC unit for the insertion loss and echo return loss values for this switch 6 ATP5 BYPASS TEST UNT 601 The ATP5 unit (Fig 8) may be used by craft as a device for through office continuity testing applications This unit would be used where throughtesting of an MFT transmission slot is required This will be useful in verifying endtoend circuit wiring integrity 60 There are no option switches associated with this unitq 7 MANTENANCE 701 Maintenance of all MFT units is by substitution The J9933TB test extender may be required for access to individual leads for maintenance testing Defective units should be returned to Western Electric for repair, *Trademark Fig 3 Bypass Transmission Unit J9933BB Page

5 1SS, SECTON SWG STA 1 T 10,1 J T 6,10 & ms5 1,9,8 A J R s 3,7 R 19 J 3 R 8 R 6!W R 6 v STA BOR 5 ( S3(SW) E G 3 T m i 1 10 R J T > ]wl R3 SWG BOR 61 S(SW) 7 NOTE : NoR/REv SWTCH S s5 Fig Schematic of J9933BB Bypass Transmission Unit Page 5

6 SECTON Fig 5 TwoWbe Transmission Unit J9933BC Page 6

7 1SS, SECTON T 37 MM T 38 ASDE z MON T T 6 5J BSDE Z 13 SW 3 REV SW P cl y 1,6 \ / C 16 REV 3 ( 1 11 % R w + o ii) 39,5 1 MON R 10 0 BSDE! Z k : $ 19 b AS 3 r5 AS 6 A B 6 5 S6 AEV, REV 3 AS l;: z 16 b 5 L LSH 56 L SH R R SCR SB SW + \ 9 MON R R 3 NC NC + B51 f BS 1: l+ & L GRD FR CONN L St+, Pig 6 Schematic of J9933BC Wire Transmission Unit Page 7

8 SECTON SERES1 JQ!J m OOR OOR El ElASE Soo Z N: NOR El WTNN LOSS cl1 u Fig 7 ATP 600/900 dc Bypass Unit 7 # u 3 E LATP5 FRONT VEU u n o $ Fig 8 ATP5 Bypass Test Unit Page 8

9 1SS, SECTON TABLE A w ELECTRCAL CHARACTERSTCS OF THE J9933BA AND BC WRE TRANSMSSON UNTS J9933BA,LA J9933BA,L,A,C (61 pf CAP) (1 6 pf CAP) J9933BC AND ATP Loss AB RN ROUT (1000 Hz) db 0 db 08 db 0 db db 06 db 10 db 06 db db 05 db 09 db 05 db ASide ERL AB with 600 or &900 7 db db 9 db db +16 F Termination 6W600 db 0 db db 0 db on the BSide 600:900 7 db db 9 db db 0 db db 0 db DC Resistance (Q) BOR N BOR OUT BOR N BOR OUT SX N* SX OUT* ASide (SWG) BSide (STA) 900 No SX, BOR With SX, BOR Connected w * J9933BC only 1, Page 9 9 Pages