long stub length rs485
The rise time can be reduced to increase stub length, as long as satisfies some challenges;


=>10x the stub prop. delay 
=&lt;10% of a data bit 
Zo error =&lt;25%


An open stub reflects 100% of the signal with twice the length delay at bus
An output cap in LPF causes Zo mismatch on attenuation with variable reflection as Zc(f) drops with rising hamonics.
steep filters , even Gaussian, can cause ISI degradation, unless "raised Cosine" type which overshoot with zero crossings same as data.