International Data Sciences Model 91 Analog Test Set
The Model 91 is a small, hand-held, battery-operated voice frequency test set capable of testing leased two or four-wire telephone lines. This test set measures the power level of a transmitted or received signal and displays the result in dBm on a four-digit LCD display. The Model 91 can monitor the transmitted or received signal with an audio speaker, which can be disabled by a front-panel switch.
The component offered is in good condition and appeared to be complete and functional when power tested. I have no knowledge of the operation of this unit so can’t test further. No instructions are included, but at the time of posting, this unit is current on the IDS Site so they should have a manual if needed. This unit sells for $395 so don’t miss this deal! As with all items I sell, this unit is being sold "as-is".
The Model 91 can transmit 5 frequencies: 404, 1004, 2713, 2804, and 3804 Hz. The 1004 Hz tone is the recommended AT&T Telephone test frequency for measuring level and channel losses. The 404, 1004, and 2804 Hz tones allow the user to quickly perform a standard Gain-Slope Measurement Test and obtain an approximate frequency response of the channel. The 2713 Hz tone allows the user to activate and deactivate standard AT&T Telephone remote loop-back equipment.
The Model 91 has an input and output impedance of 600 ohms, allowing it to drive and receive signals on leased lines. It also has a high-impedance bridge in the receiver input allowing the Model 91 to monitor and measure any signal level without loading down the signal itself. The output signal level is set at the standard 0 dBm.
SPECIFICATIONS
TRANSMITTER
RECEIVER
