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Digital Signal Identifier 1B

Differential Detector
The probe tip incorporates two pick-up plates, one above the other, which act as the signal detectors. Only the difference signal is amplified. This ensures that only signals from the pair into which the probe is inserted are processed and that signals from adjacent pairs are rejected.

Reproduces Audio Signals
The probe will reproduce audio signals directly, such as speech or base-band modem or fax tones and will warn of the presence of high speed digital circuits by producing a distinctive two-tone warning sound.

Digital Services Alarm
A two tone alarm signal is sounded if the probe detects the presence of digital services such as:
ISDN2 (IMUX 3B2T solution) 20kHz – 100kHz
ISDN2 (4B3T line code solution) 20kHz – 120kHz
ISDN2 (2B1Q line code solution, DACs & Pair Gain)10kHz – 80kHz
Kilostream 10kHz – 300kHz
ADSL (DMT, downstream) 25kHz – 300kHz/400kHz
ADSL (DMT, upstream) 20kHz – 138kHz
30 Channel PCM/Megastream 100kHz – 768kHz
CWSS (2 pair) 40kHz – 300kHz
HDSL (3pair 2B1Q) and CWSS (3pair) 40kHz – 200kHz
HDSL (2D8 CAP) 39kHz – 238kHz
HDSL (4D16 CAP 36kHz – 216kHz