05:48 Jan 8 

another terms that you didn´t ask:
in USA, the links are T1 (24 channels); the equivalent in Brazil (Europe-based) are the "E1" - 30 channels;
DDR is "discagem direta a ramal" (direct branch calling). That´s the facility you have when calling a company which, for ex., the main number is 3347-0000, and has 24 branches numbered from 01 to 23 (final number). If you call 3347-0020, you´ll reach branch #20 directly, as opposed to earlier systems, where you had to talk with the manual operator or dial 3347-0000#20.
Only to illustrate!
Good work!