Patent ID: 7743125

Claim:
A multiple port unit adapted for coupling one or more computers to multiple peripheral devices over a network, said multiple port unit comprising: plural network ports, each of said network ports being configured to couple the multiple port unit to a computer via one or more hubs over a respective network link; plural communication serial ports, each of said communication serial ports being configured to couple the multiple port unit to a peripheral device; and a control unit to interrogate the network links and to communicatively couple said communication serial ports to a selected one of said network ports based on the interrogation of the network links, the control unit further determining whether it is time to interrogate the network links; and the control unit interrogating the network links including checking an availability of a computer over each of the network links including comparing a single current time value received from the computer with a previous single time value received from the computer, wherein each of the single time values received from the computer reflects a period of time from a particular reference time of a day and wherein the control unit determines whether the computer is available solely on whether the current single time value is greater than the previous single time value; wherein said network ports are configured to couple the multiple port unit to plural computers and wherein said control unit is configured to interrogate each of the plural computers and to select an active computer to control the peripheral devices based on the interrogation of the computers; further wherein the control unit is configured to identify a network link as not operating properly based on the interrogation and to prevent further interrogation thereof for a preset period of time.