AMERITECH AM8a, Instruction Manual

Page: 77 / 152

Meter Display (18-0037) AM8a Instruction Manual
February 10, 2000 0037-S06.L_
6-8
The current measurement circuit has a 500mA slow blow fuse in series with the Tip
sense circuit. Excessive current will open the fuse and disable the current
measurements. See Section 1 for instructions on fuse replacement.
When performing current measurements, holding resistance of 10
Ω
, 330
Ω
, or 430
Ω
can be selected. With the two higher-resistance settings, the measured current may
drop after 10 minutes hold time due to heating of the line feed inductor.
6.4.6
Tone:
This selection is used to measure Level and Frequency of Tones present on the
Tip and Ring of the
LOOP
input jack. The Level is displayed in dBm and the frequency
is displayed in Hz. A measured value of "
UNDER
" in the Level display indicates the
measurement is lower than the acceptable limit. (dBm < -40). The measure display for
the tone selection is as follows:
Tone = - 10 dBm 1004 Hz
Vt-r dc = - 38.9