D105 Sending Tone

The D105 Sends tone and constantly searches for a short or ground condition. When a short is found the tone pattern changes until the fault is removed. This feature allows the user with a hand held probe at the far end to identify when a short is applied and released.


The user has two display choices when sending Simplex tone. From any mode press TONE, and SMPLX. SMPLX-1T displays analog DC Volts between Tip and Ring while sending tone. A weak 10Vdc is applied between T/R to provide the ability to see a short condition on a vacant pair. Any Tip to Ring voltage present on the pair will over-ride the weak 10V and be displayed accordingly.

SMPLX-3T mode is ideal when a short already exists on the pair. In addition to monitoring T/R voltage the tone level transmitted on both Tip and Ring are displayed. When a Tip or Ring Ground is applied the display will indicate a significant drop in Vac on the corresponding terminal.

The ideal method for sending tone is Simplex. However in conditions where sever tone bleed-over or cross coupling exists TriPlex is recommended. Since virtually all cross-coupling is eliminated with TriPlex, it is best to begin a broad search using Simplex, then switch to TriPlex to pinpoint the correct pair.

An additional advantage of using TriPlex is effectively doubling the tone level sent between Tip and Ring.

Left screen shot shows the D105 sending TriPlex tone. This pair has a Ring ground, which is indicated by a significant drop in Ring to Ground voltage.