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13

CHAPTER 3: Cable Tests

Noise

The Noise test determines if background noise is
present on the cable. A display of the test results, 
like the one below, will appear only if the test fails.

Wire Map

This test verifies a correct wiring of all four pairs in a
twisted-pair cable. Any shorts, opens, miswired pairs,
crossed pairs, shorted pairs, split pairs (during
NEXT), or reverse polarity will be displayed. The
next six screens are examples of Wire Map displays.

Cable Fails

Background Noise

25dB

Press any key

Содержание Scan-LAN 80

Страница 1: ...1000 Park Drive Lawrence PA 15055 1018 724 746 5500 Fax 724 746 0746 Copyright 1994 Black Box Corporation All rights reserved...

Страница 2: ...X FREE technical support 24 hours a day 7 days a week Call 724 746 5500 or fax 724 746 0746 Mail order Black Box Corporation 1000 Park Drive Lawrence PA 15055 1018 Web site www blackbox com E mail inf...

Страница 3: ...2 5 The Remote Unit 9 3 Cable Tests 10 3 1 Autotest 10 3 1 1 Cable Type Selection 10 3 1 2 Testing Twisted Pair Cables 11 3 1 3 Testing Coax Cables 25 3 2 Individual Cable Tests 31 3 2 1 Wire Map Twi...

Страница 4: ...Noise Threshold 49 6 6 Saving Resetting Changes 50 6 7 Resetting to the Factory Settings 51 7 Maintenance 53 7 1 Self Test 53 7 2 Power 55 7 2 1 The Scan LAN 80 55 7 2 2 The Remote Unit 56 Appendix A...

Страница 5: ...000 ft 1 61 2 to 1219 m Resolution 2 ft 0 61 m Cable Faults Types Shorts opens 2 inter mediate impedance anomalies Fault reflections threshold 4 default 4 to 10 user selectable Calibrate cable NVP 0 5...

Страница 6: ...lco ringing Nonvolatile CMOS memory Current setup parameters and cable NVP values are saved lithium battery backup Near End Crosstalk NEXT Frequency Range 5 to 10 Hz sweep in 100 KHz steps 10 to 16 MH...

Страница 7: ...oopback Attenuation Twisted pair only Frequency Range 5 to 10 MHz sweep in 100 KHz steps 10 to 16 MHz sweep in 200 KHz steps Measurement Range 0 to 40 dB 0 to 20 dB one way Accuracy 3 dB Impedance Ran...

Страница 8: ...4 line LCD display with 16 characters per line Power Main unit 2 9 volt alkaline batteries Remote unit 1 9 volt alkaline battery Size Main unit 1 7 H x 4 W x 7 6 D 4 3 x 10 2 x 19 3 cm Remote unit 1...

Страница 9: ...es critical performance characteristics of LAN cable instal lations compares the results against IEEE LAN specifications and gives a PASS FAIL indication Live network performance may also be monitored...

Страница 10: ...en 5 and 16 MHz on twisted pair networks Wire Map Tests that the UTP cable is wired correctly for the selected network Traffic Monitoring The Scan LAN 80 continuously displays the percentage of networ...

Страница 11: ...power down to conserve battery power The Buttons select the cable type from a list of preset and user defined types The buttons are also used to scroll through a list of selections The ENTER Button i...

Страница 12: ...onnectors The Scan LAN 80 has two connectors BNC and RJ 45 BNC is a shielded connector for coax cable and RJ 45 is a standard 8 pin modular jack for twisted pair cable See the figure below Figure 2 2...

Страница 13: ...cable when using Autotest to test twisted pair cable The Remote Unit when used with the Scan LAN 80 permits NEXT and attenuation measurements and allows connector wiring to be mapped Power is supplie...

Страница 14: ...problems encountered will be reported on the Scan LAN 80 s display NOTE The accuracy of cable length measurements depends upon the NVP value entered for the selected cable type Although the preset val...

Страница 15: ...ress the or button until the desired cable type is displayed Plug one end of the cable to be tested into the RJ 45 connector of the Scan LAN 80 Plug the other end of the cable into the Remote Unit Mak...

Страница 16: ...Cable Testing During Autotest the Scan LAN 80 will execute these tests Background Noise Wire Map Length and Anomalies NEXT Attenuation and Characteristic Impedance Each test is described on the follow...

Страница 17: ...w will appear only if the test fails Wire Map This test verifies a correct wiring of all four pairs in a twisted pair cable Any shorts opens miswired pairs crossed pairs shorted pairs split pairs duri...

Страница 18: ...14 SCAN LAN 80 CABLE SCANNER Wiring 1 2 3 6 1 2 3 6 4 5 7 8 4 5 7 8 1 2 Straight Thru 3 6 Straight Thru 4 5 Open 7 8 Open...

Страница 19: ...15 CHAPTER 3 Cable Tests Wiring 1 2 3 6 1 2 3 6 4 5 7 8 4 5 7 8 1 2 Open 3 6 Straight Thru 4 5 Open 7 8 Open...

Страница 20: ...16 SCAN LAN 80 CABLE SCANNER Wiring 1 2 3 6 1 2 3 6 4 5 7 8 4 5 7 8 1 2 Shorted 3 6 Straight Thru 4 5 Open 7 8 Open...

Страница 21: ...17 CHAPTER 3 Cable Tests Wiring 1 2 3 6 1 2 3 6 4 5 7 8 4 5 7 8 1 2 Cross to 3 6 3 6 Cross to 1 2 4 5 Open 7 8 Open...

Страница 22: ...18 SCAN LAN 80 CABLE SCANNER Wiring 1 2 3 6 1 2 3 6 4 5 7 8 4 5 7 8 1 2 Reversed 3 6 Reversed 4 5 Open 7 8 Open...

Страница 23: ...ive pairs for the selected LAN environment are present Listed below are the transmit and receive pairs for Ethernet and Token Ring Ethernet 1 2 and 3 6 Token Ring 3 6 and 4 5 1 2 3 6 1 2 3 6 4 5 7 8 4...

Страница 24: ...annot measure Signal to Noise Ratio Near End Crosstalk or Attenuation Length and characteristic impedance will be measured Press any key to continue with Autotest Length The length of each pair includ...

Страница 25: ...edance mismatches located between the Scan LAN 80 and the end of the cable They can be caused by a faulty punchdown block connection twisted pair networks or badly crimped cables coax networks The dis...

Страница 26: ...to 16 MHz If excessive crosstalk is detected between any pairs in the cable the following screen appears If the Scan LAN 80 measures crosstalk indicative of a split pair in the cable the following scr...

Страница 27: ...Attenuation is measured in a loopback mode between the transmit and receive pairs but is displayed as end to end loss If excessive attenuation is measured the following screen appears Characteristic...

Страница 28: ...ents for twisted pair cables Cable Length is displayed in either feet or meters on the top line of the display If the length fails to meet IEEE specifications the length display will blink The units o...

Страница 29: ...ttenuation because of a faulty wire map SNR will be displayed as N A The bottom line of the display indicates whether the cable will work in the selected LAN environment 3 1 3 TESTING COAX CABLES Set...

Страница 30: ...LAN 80 Do not locate the Scan LAN 80 in the middle of the cable Attach a terminator of the correct value for the cable type to the other end of the cable Make sure that no cable is plugged into the R...

Страница 31: ...wing pages Background Noise The Noise test is performed first to determine if background noise is present on the cable If there is too much noise the following display will appear Characteristic Imped...

Страница 32: ...isplay below will appear if the termination resistance exceeds specified limits Length and Anomalies The distance to opens shorts or anomalies is located If an anomaly is located on the cable the disp...

Страница 33: ...able type mismatches If the cable length exceeds the specified limit for the type of cable selected the following display will appear Test Results At the conclusion of the Autotest the Scan LAN 80 wil...

Страница 34: ...nated properly and no cable anomalies are present Terminator value in ohms is displayed A flashing Terminator indicates a bad terminator If the termination resistance is outside the range of the Scan...

Страница 35: ...AN 80 will automatically power down 3 2 Individual Cable Tests Wiring Cable Length and Noise can each be tested separately by the Scan LAN 80 The individual tests run faster than the full Autotest fun...

Страница 36: ...n the Wire Map test and update the display every two seconds 3 2 2 LENGTH TEST NOTE The accuracy of cable length measurements depends upon the NVP value entered for the selected cable type Although th...

Страница 37: ...he desired cable type is displayed Make sure that any terminators are disconnected when testing coax cable The Remote Unit is not required for testing length of twisted pair cable At the completion of...

Страница 38: ...play Anomalies are reflections from impedance mismatches located between the Scan LAN 80 and the end of the cable They can be caused by a faulty punchdown block connection twisted pair networks or bad...

Страница 39: ...ent The default noise threshold setting is 260 mV refer to Chapter 6 if you want to change this value Connect the cable to the appropriate connector on the Scan LAN 80 The cable should not be connecte...

Страница 40: ...ts the cable should be properly terminated If testing twisted pair cable plug the far end of the cable into the Remote Unit For coax cable connect a terminator to the far end of the cable Figure 3 3 T...

Страница 41: ...Cable Tests Set the rotary function selector to NOISE Press the or button until the desired cable type is displayed After 10 seconds the display will give a PASS or FAIL result for the test Coax Cabl...

Страница 42: ...Average shows the average noise impulses per second PK Peak shows the worst case 1 second average noise NOTE For 10BASE T cable the maximum allowable impulse noise rate is 0 2 s with a 260 mV noise th...

Страница 43: ...unit also provides audio feedback of network activity NOTE The traffic test runs continuously The Scan LAN 80 will automatically power down after 5 minutes For 10BASE T networks the Scan LAN 80 automa...

Страница 44: ...til the correct cable type is shown at the bottom of the display then press the ENTER button 5 The following message is displayed during the Traffic test Whenever there is traffic detected an audible...

Страница 45: ...verage traffic over the duration of the test Collisions shows the current collision rate over the last second expressed as a percentage of total packets transmitted Collisions are counted when runt pa...

Страница 46: ...is resolved 6 Select another test or turn the unit off when you want to stop the traffic test The unit will automatically power down after five minutes NOTE Network throughput may be impaired when tr...

Страница 47: ...y of cable length measurements depends upon the NVP value entered for the selected cable type Although the preset values will give reasonably accurate readings in most cases the NVP of your cable can...

Страница 48: ...44 SCAN LAN 80 CABLE SCANNER Figure 5 1 Connecting Unterminated Cable 50 MINIMUM LENGTH...

Страница 49: ...press the ENTER button When the display below appears set the actual length of the cable with the or button then press the ENTER button The NVP setting is stored in nonvolatile memory and will be used...

Страница 50: ...d and minimum noise threshold can be changed by the user In addition the audible tone can be enabled or disabled from the Custom Setup mode Changes are retained after the unit is powered down Set the...

Страница 51: ...shows the desired length units Press the Enter button to store the length units setting 6 3 Audible Tone An audible tone can be enabled to alert the operator to test failures network traffic during tr...

Страница 52: ...LENGTH test Any reflections less than this threshold will be ignored by the Scan LAN 80 The threshold is expressed as a percentage of the incident test pulse The currently selected fault threshold wi...

Страница 53: ...fault threshold setting 6 5 Noise Threshold The noise threshold is the minimum detection level for noise impulses measured in the NOISE test The currently selected noise threshold will be shown in the...

Страница 54: ...Saving Resetting Changes After all of the user selectable settings have been entered the Scan LAN 80 will display the following Set the rotary selector to a new test function to save the entered sett...

Страница 55: ...he Scan LAN 80 may be reset to factory settings using the RESET TO DEFAULT function All settings including audible tones the units of length minimum fault threshold minimum noise threshold NVP and cha...

Страница 56: ...ESET TO DEFAULT function Press the Enter button Press the Enter button to reset the Scan LAN 80 to factory settings or select another function using the rotary selector to abort press ENTER to reset a...

Страница 57: ...sconnect all cables and run this test periodically to assure that the unit is functioning properly 1 Set the rotary function selector to SPECIAL FUNCTIONS 2 Press the or button until Selftest is displ...

Страница 58: ...display below will appear if all tests pass 4 If any test fails the unit will beep twice then display the fault Analog failures WIRE PASS PLL PASS OVL PASS CPU PASS ROM PASS RAM PASS ANALOG FAIL CPU P...

Страница 59: ...E SCAN LAN 80 Power to the Scan LAN 80 is supplied by the two 9 volt alkaline batteries The battery compartment is accessed by sliding off the cover on the bottom of the unit The Scan LAN 80 will typi...

Страница 60: ...to change the battery Power to the Remote Unit is applied only for brief intervals during cable tests for minimal battery drain The Scan LAN 80 periodically tests remote operation and will warn the us...

Страница 61: ...ector Pairs Description 10BASE T 72 100 ohms RJ 45 1 2 3 6 Cat 5 unshielded twisted pair for 10BASE T Token Ring 62 100 ohms RJ 45 3 6 4 5 Cat 3 unshielded 4 UTP twisted pair for Token Ring Token Ring...

Страница 62: ...pecifications for the selected LAN environment 10BASE T or Token Ring The Autotest Results screen presented at the conclusion of Autotest indicates whether the cable meets IEEE specifi cations See Cha...

Страница 63: ...ength Length 100 meters Required Wire Pairs 1 2 and 3 6 Background Noise Background Noise NEXT 6 dB SNR Between 5 and 10 MHz SNR 15 dB Characteristic Impedance 100 25 ohms NEXT Between 5 and 10 MHz NE...

Страница 64: ...100 meters Required Wire Pairs 3 6 and 4 5 Background Noise Background Noise NEXT 6 dB SNR Between 5 and 10 MHz SNR 15 dB Characteristic Impedance 100 25 ohms NEXT Between 5 and 10 MHz NEXT 26 15 log...

Страница 65: ...Pairs 3 6 and 4 5 Background Noise Background Noise NEXT 6 dB SNR Between 5 and 16 MHz SNR 24 dB Characteristic Impedance 100 25 ohms NEXT Between 5 and 16 MHz NEXT 58 15 log f 0 772 5 dB equivalent...

Страница 66: ...imits Length Length 100 meters Required Wire Pairs 3 6 and 4 5 Background Noise Background Noise NEXT 6 dB SNR Between 5 and 16 MHz SNR 24 dB Characteristic Impedance 100 25 ohms NEXT Between 5 and 16...

Страница 67: ...hinNet Pass Fail Limits ThinNet Test Limits Length Length 185 meters Background Noise Background Noise 400 mV Characteristic Impedance 50 12 ohms Termination Resistance 50 20 ohms Thicknet Pass Fail L...

Страница 68: ...ignaling unshielded twisted pair cable Maximum allowable cable length is 100 meters Anomaly An impedance mismatch causing an undesired signal reflection on a transmission cable Inverted Anomaly A refl...

Страница 69: ...is surrounded by a tubular conductor which acts as a shield Coaxial cables typically have a wide bandwidth Collision The result of two stations simultaneously attempting to transmit data resulting in...

Страница 70: ...t is available with four cabling alternatives thin coaxial cable standard thick coaxial cable twisted pair and fiberoptic cable Jabber A network fault condition where one station is continuously trans...

Страница 71: ...up of bits in a defined format containing a data message that is sent over a network Plenum Cable Cable that has been certified for installation in air ducts and open spaces over suspended ceilings wi...

Страница 72: ...o shield the wire pairs from external noise Short A near zero resistance connection between two wires of a circuit Signal Noise Ratio The ratio of received signal level to noise level measured at the...

Страница 73: ...lse and the reflected pulse from an impedance mismatch on the cable such as an open at the end of the cable The length of the cable may be calculated by knowing the velocity of propagation of the puls...

Страница 74: ...nator eliminating reflections from the end of the cable Token Ring A LAN with ring topology which uses token passing to control access Twisted Pair A communication cable using a pair of wires that are...

Страница 75: ...impedance 23 27 Coaxial cables testing 63 Collisions 41 Connectors RJ 45 and BNC 8 Controls 6 Custom setup 46 ENTER button 7 Ethernet transmit receive pairs 19 Factory settings resetting to 51 Fault...

Страница 76: ...ermination resistance 28 Terminator value 30 Test results 24 29 Testing coax cables 25 Testing twisted pair cables 11 Testing 10BASE T 59 Testing cables 58 Testing Thicknet 63 Testing ThinNet 63 Testi...

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