Abstract: There is provided an interface circuit according to which a telephone or an intercom may be connected to a port of a main device including a telephone exchange function. The interface circuit includes a power supply circuit that supplies necessary power supply voltage according to the telephone or the intercom connected to the port, and a state detection circuit that detects, in a case where the telephone is connected to the port, whether the telephone is in an on-hook state or in an off-hook state, based on the value of an input impedance of the telephone, and that detects, in a case where the intercom is connected to the port, whether the intercom is in a standby state or in an activation button pressed state, based on a value of the input impedance of the intercom.

Abstract: There is provided an interface circuit according to which a telephone or an intercom may be connected to a port of a main device including a telephone exchange function. The interface circuit includes a power supply circuit that supplies necessary power supply voltage according to the telephone or the intercom connected to the port, and a state detection circuit that detects, in a case where the telephone is connected to the port, whether the telephone is in an on-hook state or in an off-hook state, based on the value of an input impedance of the telephone, and that detects, in a case where the intercom is connected to the port, whether the intercom is in a standby state or in an activation button pressed state, based on a value of the input impedance of the intercom.

Abstract: A novel separating agent for protein purification which not only can adsorb proteins in a sufficient amount for protein purification from a low concentration buffer but also can desorb the adsorbed protein easily just by altering the pH of the buffer and a simple and economical method for its production and a method for protein purification using it. One or two ligands selected from the group consisting of a ligand represented by the following formula (1): (wherein m is an integer of from 2 to 6) and a ligand represented by the following formula (2): (wherein each of R1 and R2 is independently a hydrogen atom or a C1-4 alkyl group, and n is an integer of from 1 to 6) are immobilized on a support via a urethane bond without intervention of a spacer arm.

Abstract: A novel separating agent for protein purification which not only can adsorb proteins in a sufficient amount for protein purification from a low concentration buffer but also can desorb the adsorbed protein easily just by altering the pH of the buffer and a simple and economical method for its production and a method for protein purification using it. One or two ligands selected from the group consisting of a ligand represented by the following formula (1): (wherein m is an integer of from 2 to 6) and a ligand represented by the following formula (2): (wherein each of R1 and R2 is independently a hydrogen atom or a C1-4 alkyl group, and n is an integer of from 1 to 6) are immobilized on a support via a urethane bond without intervention of a spacer arm.