I am simulating an unshielded twisted wire pair of a communication network, Controller Area Network. Bus Speeds taken into consideration are 250/500/1000/2000 kbps. Depending on the physical dimensions of the wire and insulation dielectric constant, I have computed the R,L,C,G parameters. Since, the wire length will be smaller than 300meters (i.e. considering a 1Mhz freq.), I am using lumped parameters for each section of the wire for simulation purposes. The general topology of the circuit is a 3 Node network, with line terminations of 120Ω at the two ends of the bus. For simulation purposes, one node of the network will be transmitting, and the others will be receiving. The lumped model is defined by the generic, RLCG model. There are a few things, where I cannot get my head around, need your help on it: 1. The orientation of the model? Generally, the model has R, L at the node where the current is entering the circuit. Is this a rule? 2. If I model the circuit to have a more distributed parameter, for e.g. instead of having a R,L,C,G model of one section of length 1m, I could split it up in 10 models of 0.1m for every section. Doing this resulted in a very distorted waveform, when the node is not transmitting(at 2.5V, everytime, everywhere). When I just use one model, that is lumped, the waveform is even, and almost follows the measured values. Why? 3. As I move farther away from the transmitting node, the initial spikes(transient) keep on increasing. This is not the case, in measured voltage waveforms. Why does this happen? I have attached files: Capture being the simulated circuit, 3 Node at Sender being waveforms for transmitting end, and 3 Node at Farthest end being, well that is self explanatory. '004' is the measured waveform in the lab. Thank you for your time.