Abstract: In a first embodiment of the invention, two sets of seven PN-sequences of length 128 are provided having favorable correlation properties for use as a preamble or midamble synchronization code. At the receiver a processor may be used to detect the code. In another aspect of the invention, a communication system using a synchronization code selected from sets of provided codes is claimed where the synchronization code may help to minimize possible misidentification of noise or interference by assisting in the detection of the start of a designated burst. The synchronization codes and their means for detection may be employed in various communication systems.

Abstract: In a communications network, call records are generated by a plurality of originators (CLI#1, CLI#2, CLI#3) making calls to a service provider (180). The call records are stored in a database (145) which forms part of the billing function (140) of the network. The call records for the service provider (180) are collated and sent to the service provider for processing. The service provider is provided with a system for analyzing the call records to establish the number of lost callers, rather than the number of lost calls. This is possible since the call records include the CLI information of the originators. This information, gathered over a predetermined period of time, allows the service provider (180) to estimate the number of answering stations (170) necessary to optimize call answering and minimize the number of lost callers.

Abstract: A safety support apparatus for ladders which enhances the stability of the lower end of the ladder against slipping, sliding or being jostled away from a position on the ground or other such supporting surface includes an open frame structure having a pair of laterally spaced apart A-frames. Each A-frame has a rearwardly and upwardly angled front leg and a rearwardly and downwardly angled, shorter rear leg. The front and rear legs are fastened together near their respective upper ends by an upper transversely disposed bolt, and at locations intermediate their ends by a longitudinally disposed straight side beam member. The two A-frames are held in a parallel vertical orientation by the combination of a front transversely disposed strut fastened at opposite lateral ends thereof to the upper surface of A-frame side members near their junction with the front A-frame legs, and a rear transversely disposed strut fastened at opposite lateral ends thereof to the rear A-frame legs, below the side members.