Abstract: A measurement system includes an atomizer, an impactor, a particle counter, and a discharge reservoir. The atomizer has a liquid intake port and a gas intake port configured to aerosolize a liquid received at the liquid intake port. The impactor has an inlet coupled to the atomizer and has a first output port and a second output port. The impactor is configured to separate droplets wherein those droplets smaller than a selected cut point are directed to the first output port and those droplets larger than the selected cut point are directed to the second output port. The particle counter is coupled to the first output port and is configured to count particles larger than at least one particle size cut point. The discharge reservoir is coupled to the second output port.

Abstract: A modem security access circuit device, which is coupled between a dial-up telephone line and an automatic-answering modem, includes a line matching transformer circuit which trips an incoming ringing signal for a predetermined time interval. During the predetermined interval the caller, who receives no indication of the presence of the modem, must send an access code consisting of a preselected sequence of up to ten digits from a DTMF tone pad, or else the line matching transformer circuit disconnects from the telephone line. The device also includes a decoding circuit coupled to the line matching transformer circuit for receiving the access code. If the correct access code is received, the decoding circuit activates a ring supply generator which provides an internal ring signal to activate the modem. The activated modem is then coupled to the telephone line through the line matching transformer circuit and a carrier signal is sent to the caller.

Abstract: A common telephone bell ringing device has a plurality of input terminals adapted to be connected to the ringing sides of a plurality of incoming telephone lines, an output terminal adapted to be connected to a telephone bell, a common terminal for said output and input terminals, a plurality of photoresistors connected between said output terminal and said input terminals, respectively, each being essentially non-conductive when not exposed to radiant energy and conductive when radiant energy impinges thereon, and a plurality of radiant energy sources such as neon lamps connected between said common terminal and said input terminals respectively, each neon lamp being mounted in a light tight enclosure with a corresponding photoresistor so that ringing current on one of said input terminals energizes a corresponding neon lamp to reduce the resistance of a corresponding photoresistor and permit the ringing current to pass to the bell without feedback to any other input terminal.

Abstract: Telephone command apparatus responsive to ringing current on a telephone line includes a decoder responsive to upper and lower frequency components of two-tone signals and an access and lockout device responsive to decoded signals representative of a correct sequence of two-tone signals for terminating the incoming telephone line and enabling a plurality of relays for actuation selectively in response to other two-tone signals received over the telephone line to initiate and complete one or more operations at the called location. Until the correct sequence of two-tone signals is received, the command apparatus has no effect on the telephone line to which it is connected and the line functions in the normal way. Transmittal of an incorrect series of two-tone signals to the access and lockout device disables the command apparatus and renders it incapable of responding to incoming signals for a predetermined period of time.