ACCURATE ELECTRONICS 104445A Manual
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Page 1 of 6Model 104445AJanuary 2014This document contains proprietary information and is supplied for identification, maintenance, engineering evaluation or inspection purposes only and shall not be duplicated or disclosed without writtenpermission of: ACCURATE ELECTRONICS INC By accepting this document the recipient agrees to make every effort to prevent unauthorized use of this information.Prac_104445A_RevB.pdfContents:Section 1. General 1Section 2. Application 1Section 3. Specifications 2Section 4. Installation 2Section 5. Circuit Description 3Section 6. Mechanical Outline 3Section 7. Testing and Troubleshooting 3Section 8. Maintenance 4Section 9. Warranty 4Figure 1. Circuit Description 5Figure 2. Mechanical Outline 6Figure 3. S1, S2 Locations 3Table 1. External Connections 3Table 2. Splitter/Combiner Impedance Switch Settings 2Table 3. Splitter/Combiner Attenuator Switch Settings 2Table 4. Test Guide Checklist 41. GENERAL1.01 This practice provides application, specification, circuit and mechanicaldescription, maintenance, installation, and warranty information relating toAccurate Electronics’ Dual 5 Way Balanced Active Data Bridge, Model104445A.1.02 The 104445A Dual 5-Way Balanced Active Data Bridge module(Figure 1) provides balanced termination and active level control for a single4-Wire common port and up to four 4-Wire multiple ports. Independentsplitter and combiner channels allow full-duplex (simultaneous bidirectional)data transmission.1.03 The 104445A follows a conventional split bridge format, i.e., thecommon port interfaces the multiple ports through separate splitter andcombiner channels. In the splitter channel, a single common input is dividedthrough the bridge to provide outputs for the four multiple ports. In thecombiner channel, inputs from the four multiple ports are connected throughthe bridge and to the single common output port. The common splitter inputlevel can be attenuated by one of three switch-selectable settings of 0, -7, or–25dB, and the common combiner output by switch-selectable values of 0, -16, or –25dB.1.04 The 104445A is an active bridge, that is, it includes integralamplification circuitry. Splitter gain and combiner gain at each multiple portare continuously adjustable over a –10 to +10dB range via independentsplitter and combiner front-panel level controls.1.05 All ports of the 104445A are transformer coupled, and the transformersat these ports are center-tapped to derive balanced simplex leads. Themodule’s common port can be switch-optioned for 150, 600, or 1200-ohmterminating impedance, while the terminating impedance of each multipleport is fixed at 600 ohms. The 150-ohm option affords a small degree ofamplitude equalization when the common-port facility consists of non-loadedcable.1.06 Splitter and combiner bus extension leads on the module allow from two(2) to fourteen (14) 104445A’s to be connected in tandem withoutperformance degradation, yielding a bridge system with up to 56 multipleports.1.07 A complement of 10 front-panel bantam-type jacks facilitates alignmentand maintenance of the 104445A. All ten (10) jacks are the opening type.The splitter in jack faces the common-port facility to permit measurement ofthe incoming signal level, while all other jacks face the module to allowmeasurement of the splitter and combiner levels at each port.1.08 The 104445A contains an internally regulated power supply that permitsoperation on filtered, ground-referenced –22 to –56VDC input. With allamplifiers at their maximum output levels, the module draws a maximumcurrent of 70mA.1.09 A Type-10 module, the 104445A mounts in one position of AccurateElectronics’ Type-10 Mounting Shelf, versions of which are available forrelay-rack and apparatus-case installations. In relay-rack applications, up to12 modules can be mounted across a 19-inch rack, while up to 14 modulescan be mounted across a 23-inch rack. In either case, the shelves require 6inches of vertical rack space.2. APPLICATION2.01 The 104445A Dual 5-Way Balanced Active Data Bridge is normallyused to interconnect several 4-Wire data modems to a common data channelor link. Typically, the common data link is terminated at the distant end bya central processor unit (CPU) or computer that time-sequence-polls variousremote data terminals. A 104445A is used to provide the central transmissionbridge arrangement, or hubbing network, that extends data transmission tothe outlying terminals.2.02 All ports of the 104445A are transformer-coupled, and each transformeris center-tapped to derive a balanced simplex lead. Since these ports aretransformer-coupled, modems with balanced and unbalanced terminationscan be intermixed without affecting established transmission parameters. Inaddition, transformer coupling also prevents induced transients, or noisespikes, from degrading transmission quality on cable runs in excess of 1kilofoot.2.03 The modems used with the 104445A need not share common interfacelevels. The 104445A’s active level-control circuitry can be adjusted toaccommodate any modem’s interface requirements (within the specified gainranges) without affecting the settings of the other ports. Each multiple portis equipped with independent splitter and combiner gain controls that areadjustable over a –10 to +10dB range. These controls are non-interactive,ACCURATE ELECTRONICS INCPO BOX 1654 97075-1654 8687 SW HALL BLVD 97008 BEAVERTON OR USA 503.641.0118 FAX 503.646.3903WWW.ACCURATE.ORGPractice Section 104445A Rev BDUAL 5-WAY BALANCED ACTIVE DATA BRIDGEMODEL 104445A |
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