SL1100 used for years with modem and no issue for remote database changes. Upgraded KSU from 1.5 to 7.2. Typically I call into the office and receptionist transfers to 740, modem answers and it's good, but slow. Now we get a busy signal. Manuals say I need to forward an extension to 740 but I have never done that. First system with this late version of software. Maybe needs a reboot?