The 4940A Transmission Impairment Measuring Set (TIMS) tests the capability of a telephone circuit to handle data. It measures loss, dropouts, gain hits, phase hits, phase jitter, noise-with-tone, noise-to-ground, frequency shift, message circuit noise, 3-level impulse noise, attenuation distortion, envelope delay distortion, and single frequency interference. The 4940A is also capable of running a comprehensive self-check. The 4940A does complete analog testing of voice and data channels. It is also compatible with North American Standard. The transmitter frequency range is 200 Hz to 3904 Hz with a resolution of 1 Hz. The receiver frequency range is 200 Hz to 4100 Hz with a resolution of 1 Hz. The transmitter and receiver level ranges are +10 dBm to 40 dBm with a resolution of 0.1 dBm. The impedances for the 4940A are 600 Ohms and 900 Ohms. The power requirements are 105 to 129 VAC, 60 Hz. The 4940A comes with the filters C-message, 3 kHz flat, and notch (>50 dB rejection from 995 Hz to 1025 Hz). The low-level threshold range of the 3-level impulse noise is from 30 dBrn to 109 dBrn. The mid-level threshold range is 4 dB above the low-level (maximum 109 dBrn). The high-level threshold range is 8 dB above the low-level (maximum 109 dBrn). The 4940A comes equipped with operating manual.
