Companies and individual users could connect into the PSS network using the full X.25 interface, via a dedicated four-wire telephone circuit using a PSS analog modem and later on, when problems of 10-100 ms transmission failures with the PCM Voice based transmission equipment used by the early Kilostream service were resolved, via a Kilostream digital access circuit (actually a baseband modem). In this early 1980s era installation lead times for suitable 4-wire analog lines could be more than 6 months in the UK.