Improvements in or relating to apparatus suitable for the reproduction of acoustic effects
GB272263A
Improvements in or relating to telephonic instruments
GB262626A
Improvements in or relating to apparatus capable of indicating distortion or degree of impurity of wave form of an alternating current
GB266491A
Improvements in or relating to electrostatic devices
GB271125A
Improvements in and relating to telephonic receivers
GB266802A
Improvements in or relating to rotary switches for use with electrical apparatus fortransmitting signals
GB262910A
Improvements in or relating to telephone transmitters and receivers
GB266029A
Improvements in or relating to thermionic valve amplifying arrangements
GB265662A
Improvements in loud speaking telephonic apparatus
GB264910A
Improvements in and relating to thermionic valve amplifying arrangements
GB260717A
Improvements in or relating to sound amplifying means embodying wireless telephonic receivers
GB262507A
Improvements in or relating to switch apparatus for use with telephonic receivers
GB258414A
Improvements in or relating to telephonic receivers
GB260663A
Improvements in and relating to amplifying means particularly applicable to office or public line telephonic receivers
GB258690A
Improvements in or relating to apparatus suitable for use with sound transmitting orrecording apparatus
GB257053A
Improvements in or relating to acoustic amplifying, radiating and diffusing means suitable for use with telephonic receivers and other sound producing or reproducing apparatus
GB258346A
Improvements in or relating to loud speaking telephonic receivers
GB257996A
Improvements in or relating to telephonic receivers
GB257309A
Improvements in or relating to telephone transmitters
GB259015A
Improvements in or relating to electrical transformers suitable for use with thermionic valve systems
