XL-12000B
HIGH-SPEED NETWORK MODEM
APPENDIX B: MEASURE LINE LENGTH TUT SYSTEMS 15
Appendix B: Measure Line Length
Measuring Phone Wire
1. Use a cable scanner or an ohmmeter to measure the lengths of
phone wire that will connect the modems. When using an ohm-
meter, short-circuit one end of the phone wire and measure the
resistance between the two wires at the other end .
Figure B.1 Using an Ohmmeter to Measure the Length of Phone Wire
2. Multiply the resistance by 20 to find the length of the wire in
feet. For example, 600 ohms would indicate a cable length of
about 12,000 feet: 600 x 20 = 12,000 (+/-). This formula works
for 24-gauge phone wire.
600
OHMS
Short Pair
Together
Ohmmeter
Punchdown
Block Punchdown
Block