ADTRAN's ACT 1241 channel bank is a T1 multiplexer based on the open architecture and reliability of D4 channel bank technology. It combines proven ADTRAN experience in DDS channel units and T1 interface products with interchangeable, off-the-shelf voice and common equipment. The ACT 1241 supports dedicated or switched digital, analog, and ISDN Basic Rate services over high-capacity T1 carriers.The ACT 1241 requires seven pieces of common equipment for normal operation, and accepts optional T400 equipment for additional functionality. The common equipment may be purchased individually or as a package. Two types of Line Interface Units are available: standard LIU or ACT DAX . An intelligent enhancement to the bank, the ACT DAX provides several additional features. The optional T400 units consist of an AC/DC power supply, ring generator, and T1 CSU.