The HP 4934A is a wideband (20 Hz to 110 kHz) Transmission Impairment Measuring Set (TIMS). The transmission impairment measurements which can be made are listed below. Level Frequency Noise Noise with Tone Signal to Noise Impulse Noise P/AR, (Peak to Average Ratio) Noise to Ground The HP 4934A can make measurements directly on leased lines or on dial-up lines. It has loop holding capability, a monitor speaker and butt-in connection (useful for talking to the far end of the test line). There are four permanently stored frequencies 404 Hz, 1004 Hz, 2804 Hz and 2713 Hz. Any other four frequencies may be temporarily assigned and stored by the user. The HP 4934A can test circuits using single frequency (SF) signaling - use the SF SKIP feature. SF SKIP prevents the HP 4934A from transmitting signaling frequencies in the range 2600 Hz ±150 Hz.