First Year Performance Paper - Section 2.4
2.4 Data Acquisition Hardware
The South Pole host machines comprise DOMHubs, which are standard industrial Single Board Computers, and a string processor, which is a commercially available server computer. Each DOMHub is customized with +48 Volt and -48 Volt switching regulated AC-DC single output power supplies, to supply 96 Volts to the DOMs. Wire pairs servicing DOMs are connected to custom PCI cards inside the DOMHubs called DOR (DOm Readout) cards. The DOR cards provide power, communications and time calibration signals to the DOMs. Each DOR card can be connected to two power and communication wire pairs. Each wire pair is connected to two adjacent DOMs on a string (one terminated and one unterminated to optimize communications). IceTop DOMs are served by a single wire pair. A DOMHub with a full complement of eight DOR cards can read out up to 32 DOMs In-Ice or 16 IceTop DOMs. The DOR cards used in 2005 have been replaced with a new version capable of handling 2 quads (8 DOMs), such that each DOMHub serves one complete string.
Each DOMHub is equipped with a custom PCI card called a DSB (DOR Service Board) card. The DSB card distributes the GPS time string to each of the DOR cards in a DOMHub. These signals are used to maintain timing across the array.