We Migrated a Sheffield Manufacturing Firm Off ISDN in 48 Hours. Here Is What Broke

Last Tuesday, honestly, I thought we had this one wrapped. A 28-person manufacturing firm in Sheffield, 2 office sites, PRI circuits from 2011, mobile twinning that had never worked properly. The owner wanted off ISDN before the end of the quarter. From my experience, these migrations take about 2 weeks start to finish. We did this one in 48 hours and I will tell you everything that broke. The starting state Item Detail Site A (head office) ISDN30, 30 channels, 14 handsets Site B (factory) ISDN2