  I discuss the strong link between the transmission line (TL) equation and the
TL circuit model for the charging of an electrolyte-filled pore of finite
length. In particular, I show how Robin and Neumann boundary conditions to the
TL equation, proposed by others on physical grounds, also emerge in the TL
circuit subject to a stepwise potential. The pore relaxes with a timescale
$\tau$, an expression for which consistently follows from the TL circuit, TL
equation, and from the pore's known impedance. An approximation to $\tau$
explains the numerically determined relaxation time of the stack-electrode
model of Lian et al. [Phys. Rev. Lett. 124, 076001 (2020), arXiv:1911.09924].
