SCSI - LVD & HVD ?
david_r_lamb
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Does anyone know where I could get more information on these type of scsi devices, as I was at a Job interview and they asked these type of questions, what would happen if you connected a LVD to a ???????
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HVD (High Voltage Differential SCSI)
Was created to elimanate mode noise through the cable. HVD use 2 wires per bit of date; one wire for data one for the inverse of the data.By taking the difference of the 2 signles the device can reject the common mode noise in the data, allowing for longer cables. (up to 25 meters)The inverse signal takes the place of the ground wire (danger in an SE SCSI) SCSI 1 divices were Single-ended (SE)
HVD and SE ARE NOT COMPATIBLE. If you connect an HVD device to an SE device you will fry the SE device.
They then came out with Low Voltage Differential which require less voltage than HVD and can be connected to an SE device. If you plug an LVD device to an SE device it will act like an SE devie. Cable lenth went down to 12 meters. (Still bigger than the 6 meters SE cables)