**Feature Request** From ngspice manual Chapter 6: Transmission Lines. http://ngspice.sourceforge.net/docs/ngspice-manual.pdf In order of priority: 6.4 KSPICE Lossy Transmission Lines 6.4.1 Single Lossy Transmission Line (TXL) 6.4.2 Coupled Multiconductor Line (CPL) These are preferred over the LTRA model because they run faster. 6.2 Lossy Transmission Lines 6.2.1 LTRA model The LTRA model is a well tried and tested model that spice users will be familiar with. 6.3 Uniform Distributed RC Lines 6.3.1 Uniform Distributed RC Model (URC) This is mainly of interest to IC designers and is on little use in simulations using discrete components. http://ngspice.sourceforge.net/docs/ngspice-manual.pdf Why is this feature important to you? The lossless transmisson line is very useful but for users who wants to try to simulate a realistic length of cable then the lossless models are essential. The coupled line CPL model is essential to simulate crosstalk in PCB layouts. It is useful as a real Signal Integrity tool and as an educational tool.