New USR Courier Modem

New USR Courier Modem (3CP)3453

US Robotics is now manufacturing a new V.Everything analog Courier external modem that looks like the old Courier, but is very different inside.

Pictures courtesy Alexey Stanovy, www.usrsupport.ru

If you've ever seen the insides of the old Courier, you'll realize right away there are some BIG changes here. And the big change is small size. No longer are there 2 circuit boards with plenty of components. The flash ROM size has been increased to 8 megabits, but the DSP and supervisor processor are unchanged. The DAA has been re-designed to all-electronic - there is no phone-line transformer, which might make the modem more susceptible to lightning-induced damage.

This flash ROM chip should have a sticker - there's a closeup here, and a datasheet here.

The DAA IC is a Silicon Labs Si3014-KS, and in this design, the DAA is powered by the modem - not by the phone line (which permits leased-line or 'dry' operation). Power for the DAA is provided by transistor Q8 and transformer T1 as shown here. The transformer is not a line transformer.