British Telecom


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


User Guide