Gemma Chan said in a interview that she and the other synths in the series had to go through a synth school.
The seven word activation phrase used to put new synths into setup mode [ep 1] is homage to the 2001 film A.I. in which a robot child is designed to love unconditionally and imprints onto whomever activates him with a seven word phrase.
Silas Capek is a reference to Karel Capek, writer of the play R.U.R (Rossum's Universal Robots). He also created the term robot from the Czech word "robota", which means "work".
On the Persona Synthetics website, Sally was listed as a model PS Lundstrom S6-XI. Lars Lundström is the creator of the TV series Äkta människor (2012) of which "Humans" is an adaptation.