A channel in a telemetry system is described. The channel includes a sample-and-hold circuit, a variable resistor circuit, and a control element. The sample-and-hold circuit is configured to hold a sample of a signal. The variable resistor circuit is communicatively coupled to the sample-and-hold circuit, and is configured to present a variable impedance to one or more signal lines during a time period designated for the channel. The variable impedance is representative of the sample held by the sample-and-hold circuit. The control element is configured to control the variable resistor circuit to present to the one or more signal lines an open circuit equivalent impedance during times other than the time period designated for the channel.