Conventional Systems Technical Manual - Alcad

ADJUSTMENTConfiguration of the J1 jumper (supplying power to the tap-off)In installations where the video signal is distributed via tap-offs, for the monitors to be able to receive the signal captured by thevideo unit the connection brackets must supply power through the coaxial cable to the tapped output of the corresponding tap-off.The J1 jumper permits the configuration of the connection bracket to send the necessary voltage through the coaxial cable in suchcases.Switch the J1 jumper to position B if the video signal for the dwelling comes from a tap-off. If this is not the case, leave the J1 jumperin position A.Configuration of the 75 Ω end-of-line R1 resistorTo guarantee the best possible image quality, it is important that the video line is loaded with 75 Ω in the last monitor.For this to be so, proceed as follows:If distribution of the video signal is performed with tap-offs, leave the 75 Ω resistor in the monitor of each dwelling. If a dwellinghas several monitors installed in parallel, associated to the same call, then leave the resistor only in the monitor at the end of the line.In installations with distribution in cascade, cut the 75 Ω resistor in all the monitors except the one at the end of the line.ExamplesThe following examples show the configuration of the J1 jumper and the R1 resistor depending on the type of installation.Distribution of the video signal via tap-offsDIV-024DIV-024DIV-024DIV-024BJ1R1V1MMV1DIV-024DIV-024177