Telephone system with monitor on hold feature

Telephone station set apparatus connectable to two subscriber channels, said apparatus comprising

• a handset means for transmitting and receiving audible voice communication,
• a speaker physically isolated from said handset means for transmitting to a user audible voice communication said speaker being incapable of receiving audible voice communication from said user,
• switch means for selectively interconnecting said first and second channels with said handset means and said speaker, and
• control means responsive to user actions for controlling the selective interconnections effected by said switch means,
• said control means being responsive to a first user action when a first one of said channels is connected by said switch means to said handset means for a first telephone call, for controlling said switch means to disconnect said first channel from said handset means and to connect said first channel to said speaker to monitor said first call,
• said control means being further responsive to a second user action during the continued monitoring of said first call, for controlling said switch means to connect a second one of said channels to said handset means for a second telephone call.

A method of controlling the selective interconnection of a plurality of communication channels to a handset and a speaker in a telephone station set, said method comprising

• in response to a NEWCALL signal from a user, connecting said handset to an idle one of said channels,
• in response to a PRIVACY signal from said user, moving, to said speaker, the connection of said channels that are connected to said handset,
• in response to an EXCHANGE signal from said user, exchanging connections such that said channels connected to said handset prior to receipt of said EXCHANGE signal are thereafter connected to said speaker, and such that said channels that are connected to said speaker are thereafter connected to said handset;
• and
• in response to a CANCEL signal from said user, disconnecting said handset from at least one of said channels that are connected to said handset prior to receipt of said CANCEL signal.

A telephone station set apparatus connectable to first and second communication channels, said apparatus comprising

• CANCEL, EXCHANGE, NEWCALL and PRIVACY user control buttons,
• first and second switch-hook means connected to said first and second communication channels, respectively, each of said switch-hook means having on-hook and off-hook states,
• first and second hybrid means for interfacing said first and second communication channels, respectively, to a first signal path and a second signal path,
• switching means selectively connecting said first signal path and said second signal path to a first audio means for transmitting and receiving audible voice communication and to a second audio means for transmitting audible voice communication,
• control means for controlling said first and second switch-hook means and said switching means responsive to said PRIVACY button during the off-hook state on said first communication channel for a first call, for disconnecting said first communication channel from said first audio means and connecting said first communication channel to said second audio means to monitor said first call, said control means further responsive to said NEWCALL button for connecting said first audio means to said second of said communication channels and for changing the state of said switch-hook means of said second communication channel to off-hook to establish a second call,
• said control means is responsive to said CANCEL button for disconnecting said first audio means;
• and
• said control means is responsive to said EXCHANGE button for disconnecting said first communication channel from said second audio means and said second communication channel from said first audio means, and connecting said second communication channel to said second audio means to monitor said second call and connecting said first communication channel to said first audio means for said first call.

A combination for providing a monitor-on-hold feature for telephones, said combination comprising an ISDN switching system connected to a telephone network and an ISDN telephone station set, said ISDN switching system responsive to a switching system control means and connected via a digital subscriber line comprising first and second B-channels and a D-channel to said ISDN telephone station set,

• said ISDN telephone station set including
• NEWCALL and PRIVACY user control buttons,
• splitter/combiner means for digitally interfacing said first and second B-channels and said D-channel of said digital subscriber line with a first B-channel path, a second B-channel path, and a D-channel path, respectively,
• a first coder/decoder for converting between digital voice signals, received from said first B-channel via said splitter/combiner means and said first B-channel path, and analog voice signals,
• a second coder/decoder for converting between digital voice signals, received from said second B-channel via said splitter/combiner means and said second B-channel path, and analog voice signals,
• first audio means connectable to said first B-channel path for audibly transmitting and receiving voice communication,
• second audio means connectable to said second B-channel path for audibly receiving voice communication,
• speaker switch means having a first position for selectably connecting said second audio means to said second B-channel and a second position disconnecting said second audio means from said second B-channel, and
• station set controller means responsive to actuation of said PRIVACY button during a first telephone call comprising a connection from said switching system to said first audio means via said first B-channel, said splitter/combiner means, said first B-channel path and said first coder/decoder, for placing said speaker switch means in said first position and sending a message to said switching system on said D-channel via said D-channel path, said splitter/combiner means and said D-channel to said switching system control means,
• said switching system control means responsive to said message for controlling said switching system to route said first call to said second audio means of said station set via said second B-channel, said splitter/combiner means, said second coder/decoder, and said second B-channel path to monitor said first call,
• said station set controller means further responsive to actuation of said NEWCALL button for sending a second message to said switching system on said D-channel via said D-channel path, said splitter/combiner means and said D-channel to said switching system control means,
• said switching system control means responsive to said second message for controlling said switching system to connect said first B-channel to said first audio means via said splitter/combiner means, said first coder/decoder, and said first B-channel path as a second call.