ATT System 25 Reference Manual
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TECHNICAL SPECIFICATIONS Analog Transmission Characteristics (Contd) Quantization Distortion: SIGNAL LEVELDISTORTION LEVEL +2 to -30 dBm0 35 dB -40 dBm029 dB -45 dBm025 dB Sampling Rate:8 kHz Terminating Impedance:600 ohms Trunk Balance Impedance:600 ohms or Complex Z (selectable) Echo Return Loss: The echo return loss of the switching equipment is infinite. The echo return loss of the station equipment can be engineered for greater than 18 dB over the range of 500 Hz to 2500 Hz. Loop Resistance: l TN742—Loop resistance of up to 1300 ohms, including the station l ZTN78—Loop resistance of up to 100 ohms not including the station (2000 feet with No. 24 AWG.) Connection Bandwidth: 64 Kbits Steady State Noise Level: The steady state noise level presented to any busy path does not exceed 23 dBrnc during the busy hour. Impulse Noise: The impulse noise is 0 count (hits) in 5 minutes at +55 dBrnc during the busy hour 5-21
TECHNICAL SPECIFICATIONS Analog Transmission Characteristics (Contd) Single Frequency Return Loss (Talking State): Station to station—exceeds 12 dB Station to 4-wire trunk connection—exceeds 14 dB Station to 2-wire trunk connection—exceeds 12 dB Peak Noise Level: Analog to analog—20 dBrnc Analog to digital—19 dBrnc Digital to analog—13 dBrnc 5-22
ENVIRONMENTAL REQUIREMENTS Floor Plans And Layouts Table Top Space Wall Space Requirements Temperature and Humidity Air Purity Lighting Electrical Noise/Radio-Frequency Interference (RFI) Environmental Considerations for ATL Cordless Telephone Set AC Power Requirements Grounding Lightning Protection6-1 6-4 6-4 6-4 6-5 6-5 6-5 6-6 6-8 6-10 6-10 -i-
Figures Figure 6-1.Typical System 25 Equipment Area Floor Plan 6-2 Figure 6-2.Typical System 25 Equipment Area Elevation Plan 6-3 Figure 6-3.AC Power Distribution - Multiple Cabinet System 6-9 -ii-
ENVIRONMENTAL REQUIREMENTS ENVIRONMENTAL REQUIREMENTS This section provides information on floor and wall space requirements for System 25 cabinets and associated peripheral equipment.Also included are specifications for temperature,humidity, air purity, lighting, electrical noise (RFI) suppression, power, grounding, and lightning protection. Floor Plans And Layouts Floor plan arrangements will vary depending on the available equipment area and anticipated system growth. A typical floor plan is shown in Figure 6-1. The floor must be tiled or suitably sealed, level, and free from vibration. Allow for a minimum unobstructed clearance of 7 feet above the floor throughout the equipment area. Do not locate the equipment in areas: l Where it might be subjected to excessive vibrations or disturbed by moving equipment such as hand trucks and transporters. l Where noise levels may exceed 90 dB. l Susceptible to flooding. Maintain clear access to the equipment area for both installation and maintenance purposes. The wall behind the system cabinet must be clear of all objects (pictures, shelves, or windows) that might interfere with system installation.The entire area behind the cabinet and to the side as shown on Figure 6-2 must be reserved for the cross-connect field and cable access. Also, room for system growth should be considered. 6-1
ENVIRONMENTAL REQUIREMENTS SYSTEMCABINETS(FOOTPRINT) FRONTNOTE 3BACKBOARD TERMINATION FIELD (NOTE 4) TABLE NOTES: 1. 115V AC, 60 Hz, 15 AMP OUTLETS (HUBBELL 5262 OR EQUIVALENT) MUST BE LOCATED WITHIN SIX FEET (1.8m) OF SYSTEM CABINETS. 2. MULTIPLE CABINET SYSTEMS REQUIRE TWO QUAD OUTLETS, SINGLE CABINET SYSTEMS REQUIRE ONE QUAD OUTLET. 3. ALLOW AT LEAST 24 INCHES OF SPACE IN FRONT OF CABINETS. TABLE MUST BE ABLE TO SUPPORT 250 POUNDS. 4. BACKBOARD IS 3/4 INCHES THICK BY 48 INCHES WIDE BY 72 INCHES LONG Figure 6-1.Typical System 25 Equipment Area Floor Plan 6-2
ENVIRONMENTAL REQUIREMENTS Figure 6-2. Typical System 25 Equipment Area Elevation Plan 6-3
ENVIRONMENTAL REQUIREMENTS Table Top Space The following system equipment requires (customer provided) table top space in the equipment area: l System Cabinets:Each cabinet is 13 inches high, 17 inches wide, and 21 inches deep. A 3-cabinet system requires a vertical space of approximately 40 inches and a 17-inch by 21-inch table top space.Each cabinet weighs approximately 75 pounds. Place the cabinets on a desk or table top that is about 18 inches high and capable of supporting at least 250 pounds. The cabinets must not be placed on the floor. l System Administration Terminal (SAT) Model 703: The SAT should also be located near the system cabinets and plugged into the same AC outlet. It is 12 inches wide, 10 inches long, and 3 inches high. l Digital Tape Unit: The Tape Unit (Model DC5 Digital Data Recorder) should also be located near the system cabinets.It is 5 inches wide, 2 inches high, and 10 inches long. l SMDR or Call Accounting System (CAS): The AT&T Model 572 printer used with SMDR is approximately 16 inches wide, 12 inches long, and 6 inches high. The CAS runs on the AT&T PC 6300. The printer and the PC should also be located near the system cabinets. Wall Space Requirements The customer-provided backboard for the cross-connect field should be approximately 3/4 inch thick, 4 feet high, and 8 feet wide.Mount the board 30 inches above the floor. The board must conform to national and local fire safety codes. If existing cross-connect hardware is reused,the space requirements and hardware requirements must be shown on the floor plan.Contact your AT&T Technical Consultant for assistance in planning for reuse of existing equipment. Temperature and Humidity The System 25 equipment should be installed in a well-ventilated area. The equipment must be located in an area with an ambient temperature between 40 degrees and 104 degrees Fahrenheit (5 and 40 degrees Celsius).The relative humidity must be less than 95%, noncondensing. These parameters should be maintained 24 hours a day, 7 days a week. 6-4
ENVIRONMENTAL REQUIREMENTS Air Purity The cabinet should not be installed in an area where the air may be contaminated with any of the following: l Excessive dust,lint, carbon particles, paper fiber contaminants, or metallic contaminants l Contaminants expelled by office copying machines l Highly corrosive atmosphere within an enclosed area or atmosphere containing vaporized chemical compounds that may condense on the equipment l Explosive or flammable atmosphere. Lighting Lighting should be adequate to allow administration and maintenance personnel to perform their tasks.The recommended light intensity level is 50 to 70 footcandles. This level complies with the Occupational Safety and Health Act (OSHA) standards. Electrical Noise/Radio-Frequency Interference (RFI) In most cases, electrical noise is introduced to the system through trunk or voice terminal cables. However, electromagnetic fields near the system cabinets may also induce noise in the system.Therefore, the system cabinets and cable runs should not be placed in areas where a high electromagnetic field strength exists. Radio transmitters (AM or FM), television stations, induction heaters, motors (with commutators) of 0.25 horsepower (200 watts) or greater, and similar equipment are leading causes of interference. Small tools with universal motors are generally not a problem when they operate on separate power lines. Motors without commutators generally do not cause interference. Field strengths below 1.0 volt per meter are unlikely to cause interference. Field strength can be measured by a tunable meter such as the Model R-70 meter manufactured by Electro-Metrics Division or broadband meters such as the HOLADAY* HI-3001 meter or Model EFS-1 meter manufactured by Instruments for Industry, Inc. The field strength produced by radio transmitters can be estimated by dividing the square root of the emitted power in kilowatts by the distance from the antenna in kilometers. This yields the approximate field strength in volts per meter and is relatively accurate for distances greater than about half a wavelength (150 meters for a frequency of 1000 KHz). * Trademark of Holaday Industries 6-5
ENVIRONMENTAL REQUIREMENTS Environmental Considerations for ATL Cordless Telephone Set The ATL Cordless telephone set uses standard radio transmission technology to pass communications between the handset and the base. This radio transmission is susceptible to Radio Frequency Interference as explained on the previous page. The ATL Cordless Telephone performs best when it is operated in an area free of the following devices and materials: l Metals (including steel, aluminum, etc. ) — — — — — — —metal reinforced ceilings metal window frames concrete reinforced with metal sheet metal walls steel I-beams metal studs in walls screens and fences. l Some solid structures, such as: — moist concrete walls — brick walls — steel reinforced concrete walls. l Computing equipment (devices equipped with a microprocessor) — personal computers — facsimile machines — communication system control units — uninterruptible power supplies (UPS) — copier machines. l Electromagnetic sources — industrial machinery — electric motors. 6-6