Related Manuals for METROTEC VNA-70A
Summary of Contents for METROTEC VNA-70A
- Page 1 Voice Network Analyzer MODEL VNA-70A Instruction Manual P/N 82-70-027 February 2004...
- Page 2 This page is intentionally blank.
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Page 3: Table Of Contents
TABLE OF CONTENTS 1.0 INTRODUCTION 2.0 GENERAL DESCRIPTION 3.0 CONTROLS 4.0 OPERATION 4.1 BATTERY TEST 4.2 BRIDGING AND TERMINATING 4.3 VOICE NETWORK ANALYZER 4.3.1DC VOLTS 4.3.2DC MILLIAMPERES 4.3.3DBm 4.3.4AC VOLTS 4.3.5FREQUENCY 4.3.6TONE GENERATOR 4.3.7OHMS 4.4.DIGIT DISPLAY 4.4.1.OPERATION 4.4.2.DIAL PULSE LEVEL SELECT 4.5.MONITOR SPEAKER 5. -
Page 4: Introduction
C. DIGIT DISPLAY -- displays numbers as they are dialed. D. AUDIO MONITOR -- allows input signals to be monitored via a built-in speaker. In connection with these features, the VNA-70A may be operated in either of two modes: LINE BRIDGING -- allows measurements to be made without loading the phone line. -
Page 5: Controls
3. CONTROLS A. On/Off/Volume Control B. Telephone Line Jack C. Butt Set/CPE Jack D. Setup Switch E. Test Mode Switch F. OHMS Switch G. Audio Monitor Speaker H. Display Screen; Super-Twist high contrast I. Battery Charging Jack J. Dial Pulse LEVEL SELECT (Located inside battery compartment) -
Page 6: Operation
“off hook” condition on the phone line, and is selected by setting the switch to the TERM (down) position. In this setup the VNA-70A presents a fixed 600 Ohm AC load and a variable 50 to 300 Ohm DC load to the line. The Line Bridging test setup is the equivalent of an “on hook”... - Page 7 4.3.1 DC Voltage appears in the upper left-hand section of the screen. A “+” or a “-“ precedes the voltage value shown to indicate its polarity. The VNA-70A resolves voltage to the nearest ½ volt, therefore the fractional DC voltage value is always a “.0” or a “.5”. An over range condition is indicated by a ▲▲▲...
- Page 8 Frequency of the input signal appears in the lower right=hand 4.3.5 section of the screen. The VNA-70A resolves frequency to the nearest cycle. An over range condition is indicated by a ▲▲▲ reading. Note: due to noise, it is normal for a low frequency reading to sometimes be displayed even with no input.
- Page 9 If the VNA-70A is to read pulse digits at a Central Office or at a D.I.D. terminal, set the switch to the UP position.
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Page 10: Voice Network Analyzer
The VNA-70A is equipped with a 9-Volt rechargeable Ni-Cad battery. When the battery runs down, recharge by inserting the plug from the recharging transformer into the Battery Charger jack on top of the VNA-70A and plugging the charging transformer into a 110 to 120-Volt AC source. -
Page 11: Application Notes
Life Hours APPLICATION NOTES Probably the most unique single feature of the VNA-70A Voice Network Analyzer is its ability to make simultaneous measurements of line voltage, loop current, dB level, and frequency. Not only does this greatly simplify the measurement process by eliminating the need for mode and range switching, but it also lets you monitor the interactions of these parameters in everyday situations -- a very important feature in telephony. - Page 12 7.1. Telephone Line Testing 7.1.1. Stand-Alone Use With the VNA-70A’s MODE Switch in the TEST position and the SETUP switch in the BRIDGE (center) position, connect the phone line to the LINE jack. The DC Volts section of the display screen reads the C.O. talk battery voltage.
- Page 13 Frequency: Frequency Range Resolution Accuracy +/-0.2 % of FS Minimum Input Level Maximum Input Level 125 Volts AC DC Ohms: Range 25K Ohms Resolution Ohms Accuracy +/-2.0 % of FS Loop Ohms: Range Ohms Resolution Ohms Voltage Range (Bridge) Volts DC Current Range mA DC TONE GENERATOR:...
- Page 14 7.1.2. Butt-Set Use With the VNA-70A’s MODE switch in the TEST position, connect a butt- set to the SET jack and set the SETUP switch on the VNA-70A to the BRIDGE (center) position. Now connect the phone line to the LINE jack.
- Page 15 Dial a C.O. quiet termination with the butt-set. Switch in the VNA-70A’s built-in load by setting the SETUP switch to the TERM (down) position. Now hang up the butt-set. The VNA-70A will hold the line and provide a precise 600 Ohm quiet termination on your end of the line. Broad-band (un-weighted) noise may now be read directly from the dB section of the display screen.
- Page 16 SETUP switch to the BRIDGE (center) position. A VNA-70A at the other end of the line may then be used to send a 1004 Hz tone to you. Measure its level with your VNA-70A terminating the line and the butt-set on hook.
- Page 17 Dialing patterns may be checked in the DIGITS mode with the phone line connected to the LINE jack and the dialer connected to the SET jack (the VNA-70A should be in the BRDG mode). Switch to the TEST mode to test line interface parameters.
- Page 18 15.0 milliamperes likely indicates a bad connection. c. Dial tone can be heard by adjusting the volume control on the VNA-70A. A level of between -20.0 dBm and -12.0 dBm should be seen in the upper right-hand corner of the display.
- Page 19 It should be noted that the tones and levels given in the following examples are present for very short periods of time and that the VNA-70A updates its display one time per second. Therefore, it may not be possible to read the shorter tone bursts in every case. Care must be used in observing the display so that readings are not missed.
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Page 20: Warranty
The factory assumes no responsibility for consequential damages resulting from the use of this product. NOTE: The VNA-70A is for temporary connection to the telephone lines for test purposes only. It is intended for use only by qualified technicians familiar with telephone line servicing problems. The VNA-70A is an FCC registered device.
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