Abstract: A composite membrane and process utilizing the membrane which is capable of selectively removing particles such as viral particles from a solution such as a protein solution is provided. The membrane comprises a porous membrane substrate, a surface skin having ultrafiltration separation properties and an intermediate porous zone between the substrate and the skin which intermediate zone has an average pore size smaller than that of the substrate. The intermediate zone is free of voids which break the skin and which directly fluid communicate with the substrate. The composite is capable of a log reduction value of at least 3 (99.9% removal) of particles selectively from solution.

Abstract: A composite membrane and process utilizing the membrane which is capable of selectively removing particles such as viral particles from a solution such as a protein solution is provided. The membrane comprises a porous membrane substrate, a surface skin having ultrafiltration separation properties and an intermediate porous zone between the substrate and the skin which intermediate zone has an average pore size smaller than that of the substrate. The intermediate zone is free of voids which break the skin and which directly fluid communicate with the substrate. The composite is capable of a log reduction value of at least 3 (99.9% removal) of particles selectively from solution.

Abstract: A PBX system is responsive to an incoming call which is directed to an adjunct of the system for sending a ringing signal over a station facility to the adjunct. When the adjunct goes off-hook, the system outputs to the adjunct over the station facility multi-frequency tones containing information associated with the incoming call prior to establishing a connection between the adjunct and calling party. The information selects the proper operating mode of the adjunct and provides other call processing information to the adjunct. The adjunct communicates information to the PBX using a switch-hook flash and multi-frequency tones.

Abstract: Composite ultrafiltration membranes are disclosed which are produced by forming an ultrafiltration membrane structure on a preformed microporous membrane.

Abstract: An improved adjustable convalescent crutch is provided comprising a top pair of spaced vertically extending support members, each support member carrying a plurality of apertures therethrough, telescopical with respect to a bottom portion of the crutch having a pair of vertically extending support members, spaced apart at the top of the bottom portion, each support member carrying a plurality of apertures therethrough, and converging together towards the bottom to be affixedly joined together in a "Y-shaped" configuration whereby only one of the support members continues down to form the foot of the crutch of the same diameter and material as the one support member, comprising the bottom of the "Y-shaped" configuration.

Abstract: There is disclosed a combined business communication system and an ACD system where each station in the system is available to handle, on a per call basis, either ACD or regular incoming calls. The system is arranged to accept from any user at any station an ID uniquely associated with that user. The ID in turn then controls the ACD system to direct calls to the user in accordance with the ID information without regard to the station location of that user. Calls between system users are completed either in accordance with station identification numbers or in accordance with the ID number of the desired user.

Abstract: When a standard business office communication system is combined with ACD features, it is necessary to design the system to accommodate a variety of operational modes. Two such modes are handset operation, where a station user talks and listens via a conventional hand-held instrument, and headset operation where the user has an earphone and mouthpiece supported by the head. In headset operation, the station is made to appear off-hook permanently and incoming calls are signaled by a short burst of audio tone followed by an automatic connection to the called party. In handset operation, ringing signals must be applied to the station, and these signals continue until the incoming call is answered by a subsequent off-hook condition of the station. The disclosed arrangement allows each station to operate in either mode on a per call basis.

Abstract: A telephone signaling interface (I1) enables compatible communications between a modified telephone station set (S1) and a key telephone system (KTS1). Separate alternating voltage control signals from the key telephone system (KTS1) are amplitude and polarity modulated and combined by the interface (I1) to provide ringing, switchhook supervision and visual signaling to station set (S1) over a single signaling wire pair (C1). Current flow on the signaling pair (C1) in one direction provides visual signaling while distinguishable amounts of current flow in the opposite direction provide the supervision and ringing signals. Interruption of the supervision current is converted by interface (I1) into an A lead supervision signal for the key telephone system (KTS1). Voice communication between the modified station set (S1) and the key telephone system (KTS1) occurs over a separate voice communication pair (V1).

Abstract: A telephone station set (S1) is arranged to communicate voice signals over a voice communication pair (V1) and to communicate ringing, switchhook supervision and visual signaling over a separate signaling pair (C1). An amplitude and polarity modulated alternating voltage on the signaling pair (C1) provides current flow in one direction for visual signaling while distinguishable amounts of current flow in the opposite direction to provide switchhook and ringing supervision. The switchhook supervision current and the ringing signal current both flow through a series connection of a buzzer (B1) and a break switchhook contact (SH2) in the telephone station set. An off-hook condition at the telephone interrupts current flow on the signaling pair (C1) providing a switchhook supervision signal while simultaneously terminating the ringing signal.