The Plantronics t10H allows the use of any Commercial H-Series (e.g H251 ) headset top on the new T10 platform. Single-line telephone On-line indicator and headset stand included Volume and tone control Mute with indicator light Flash and redial On/off switch for ringer Cables included with Quick Disconnect Replaces the SOHO1870-11 (P/N 46578-01) Plantronics Part#: 92157-01 Plantronics redesigned a component of the T10H and successfully tested the solution at two sites that had previously experienced T10H disconnecting during a call when used with a PBX. All T10H units will have the redesigned component.