Presentation on theme: "Principles of Voice & Data Lesson 4: Troubleshooting Bellevue Community College Bob Young, Instructor."— Presentation transcript:
Principles of Voice & Data Lesson 4: Troubleshooting Bellevue Community College Bob Young, Instructor
Troubleshooting Terms Short A connection between two wires where no connection is intended
Troubleshooting Terms Open No connection, typically where there should be one
Troubleshooting Terms Terminator A line ending, typically a connector Example: RJ-45
Troubleshooting Terms Cross Def. 1: two wires are touching ("crossed") where they shouldn't be Def. 2: two wires are reversed in a connector (ex. - Pin 2 wired to Pin 3 and Pin 3 wired to Pin 2)
Troubleshooting Terms Roll Two wires of the same pair are reversed at opposite ends of the cable
Important Distinction Be sure you understand the difference between a "crossover cable" and a "rollover cable"
Troubleshooting Terms Polarity Associated with the positive and negative terminals of the source DC voltage
Troubleshooting Terms Split One wire of one pair is crossed with a wire from another pair
Troubleshooting Terms Line Imbalance Unequal voltages on the two wires in a pair. This results in distortion, loss, and noise.
Troubleshooting Terms Loopback Testing Testing from one end a line. A signal is sent, then "looped back" and measured at the same end.
Troubleshooting Terms End-To-End Testing Testing from both ends of a line. A signal is sent from one end, then measured at the far end.
Analog Troubleshooting Tools
Butt Set Telephone Line Test Set Telephone Lineman's Test Set Line Test Set Handset Lineman's Handset
TS-22 Butt Set
TS-19 Butt Set
TS-22A Data Safe Butt Set
TS-250 ISDN Test Set
TS-1000 ADSL Test Set
Load Coil Detector (Model 88)
TS-100 TDR Cable Fault Finder
77HP Tone Generator
77M Tone Generator
200EP Probe (Inductive Amplifier)
200B Probe (Inductive Amplifier)
TIMS (Transmission Impairment Measuring Set)
Troubleshooting Analog Lines
Line Level Test Milliwatt test Level test Loss test 1000 Hz tone test
Quiet Termination Test Quiet test Noise test
Ringback Test An automated system. The tester dials a number at the CO, then hangs up. The CO equipment then calls the number that the tester called from.
ANAC Automatic Number Announcement Circuit Dial the ANAC number, and a computer generated voice speaks the number of the line you're testing Often accomplished by Caller ID now ANAC works on unlisted numbers
DATU Direct Access Testing Unit Allows you to do user-controlled tone generation tests See next slide, "DAMT"
DAMT Direct Access Mechanized Testing Allows you to do user-controlled tone generation tests See previous slide, "DATU"
Echo Test Repeats every tone you generate Useful for verifying that you are generating valid DTMF tones
Troubleshooting Digital Lines
Check Clocking #1 Also called "synchronization" On a T1, improper clocking may produce a "Sync" error light On a T1, improper clocking may produce a high BER (Bit Error Rate)
Check Clocking #2 On a voice circuit, improper clocking can be heard on the phone or with a butt set as clicking sounds On a data circuit, improper clocking may show up as random data loss or data errors
Bit Error Rate Not always related to clocking Digital equivalent of signal-to-noise ratio S/N ratio can be measured on digital voice circuits in the analog portion BER can be measured on all digital circuits, whether voice or data Causes: line loss, reflection, other
ISDN Troubleshooting #1 Verify that the SPID is programmed correctly SPID = Service Profile Identifier Assigned by the service provider Programmed in the ISDN "modem" or terminal adaptor
ISDN Troubleshooting #2 Verify that the LDN is programmed correctly LDN = Local Directory Number Assigned by the service provider Programmed in the ISDN "modem" or terminal adaptor
ISDN Troubleshooting #3 Verify that the terminator is installed (Contains two 100 ohm resistors: pins 4 & 5, pins 3 & 6)
ISDN Troubleshooting #4 Make sure the proper encoding format is programmed For North America, -law For UK and Europe, a-law