Electrical connectors – With insulation other than conductor sheath – Plural-contact coupling part
Reexamination Certificate
2000-02-10
2003-04-01
Nguyen, Khiem (Department: 2839)
Electrical connectors
With insulation other than conductor sheath
Plural-contact coupling part
Reexamination Certificate
active
06540562
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The invention relates to a panel system for communication jacks, also known as jackfields. A jack, as the term is used hereafter, is an individual female contact, for mechanical and electric cooperation with a corresponding male jack plug.
2. Description of the Prior Art
A jack-field is an array of jacks used to cross-patch audio, video or digital signals. The jackfield also serves as a test or monitoring point for these same signals. Jackfields are used where considerable quantities of audio, digital or video signals need to be interconnected in varying configurations. The primary industries are telecommunications, broadcast, cable, duplicating and recording.
The jackfield usually has a generally flat face plate with a plurality of holes, one hole for each jack. The signals coming to and exiting the jackfield are interfaced at the rear of the jackfield. The communication jacks accept standard jack plug patch cords, to effect the desired interconnection, or patch, between two jacks at the front of the panel system. The jackfields are usually rack-mounted. Other names used to describe jackfields are patch-field, patch-bay, bay, audio bay or video bay.
The jacks are available in different types such as video, digital video, longframe audio and bantam audio. The invention is directed primarily to longframe audio and bantam audio jacks.
Longframe and bantam (a.k.a. TT) audio jacks are the most traditional of the types of jacks used in jackfields. They are used mainly for audio, digital audio and RS422 signal patching. These jacks have a very specific range of function and design. The functions of the two are the same with the difference only in their physical size. The longframe is the larger of the two, and is the jack that was used in the early telephone switchboards. Bantam jacks are used extensively in modern applications because they conserve space. Bantam jacks have been available for 30+years. The telecommunications industry has used them for many years with the broadcast industry accepting them in large quantities only over the past 10 years. Large quantities of the longframe jacks are still used and generally remain the preferred jack if space is not an issue. The jacks are available in different circuit configurations, with different switching capabilities, but all with very distinct and unified physical design making these jacks a very unique product “family”. All the jack models are the result of military design and mate with one basic patchcord plug style, again with size being the only real difference between bantam and longframe. Bantam jacks are sometimes referred to as “TT” or “tiny telephone” jacks. They are one and the same.
The jacks are available with rear terminals that accept wire-wrap connection or with terminals designed for soldering.
A pre-wired jackfield is an array of jacks that are wired to some type of other interface. Most users of jackfields do not want to wirewrap or solder directly to the bantam or longframe jacks. They will specify the type of interface/connection they would prefer. Because the jacks themselves cannot economically or practically be directly fitted with other types of interfaces, manufacturers solder or wire-wrap wires to the jacks and attach these wires to the type of interface the customer has requested. Thus, the term pre-wired jackfield. The purpose is to save the customer installation time and enhance functionality and serviceability of the jackfield. The pre-wired jackfield has been a high demand product for the past 30 years. Many manufacturers have developed standard interfaces that include punch terminals, multipin connectors, more accessible wirewrap and solder pins, screw terminals and more.
Normals are circuits that connect two jacks without the use of a patchcord. The telephone operators switchboard did not need these circuits because there were no connections that would“normally” be interfaced as a default. Someone would get a very large telephone bill. The operator had to use a patchcord for every desired connection. But in the current day applications where these jacks can exist in one location in thousands, using patchcords in the front of the rack for every required patch would be virtually impossible. Therefore, the system designers will put an input and output jack vertically adjacent to each other. The jacks are connected at the rear to each other via some extra interface terminals provided on the jack (solder or wirewrap). The jackfield manufacturer wires jumpers between these extra terminals. The signal coming to one jack is now connected to the other jack as the default, or “normal” configuration without the use of a patchcord. These extra interface terminals on the back of the jack are connected to switching contacts in the jack. When a patchcord is inserted into either of these jacks from the front, the switching contacts in the jack break, thus the “normal” signal path is broken. The signal now goes through the patchcord for patching to a new location. There are two types of “normalling”, “full normalling” and “half normalling”. Full normalling is described above where the normal signal path is broken if a patchcord is inserted into either of the vertically adjacent jacks. Half normalling is a variation, where the signal path is broken if a patchcord is inserted into the bottom jack of the two vertically adjacent jacks, but it is not broken if a patchcord is inserted into the top jack. This allows the signal to be monitored without interupting the signal path. Real-time testing of television broadcast signals can be accomplished this way, for example.
The audio industry in general has many different philosophies regarding grounding of audio systems. Jackfields must thus accommodate different preferences for grounding methods. Each jack has a ground connection and in a jackfield there are many jacks. Some designs require the grounds for each jack to be kept separate, while other designs require all the jacks to have a common ground. Another method is to have all the input grounds common and all the output grounds common. Still another is to have the vertically adjacent pairs of jacks common in terms of grounding, but isolated from the other pairs.
Wiring jacks out to some other type of interface is very time consuming, and this labor forms a considerable part of the cost in this type of product. As an alternative to using wire in pre-wired jackfields, jackfields have been designed using printed circuit boards (PCBs) that connect the jacks to the desired rear interface. There are, however, limitations that make this method, as it is known, useful only for certain applications.
The following describes possible prior art for printed circuit board jackfields using traditional longframe and bantam audio jacks.
1. Jacks with solder terminal rear interface.
No known prior art, solder terminals are an awkward shape for inserting into a printed circuit board.
2. Jacks with wirewrap rear interface.
2A. The small diameter square terminals used for wirewrap are suitable for inserting into a PCB (printed circuit board) even though this was never intended. This procedure has been followed by various companies with limited success for many years. The configuration is to have one mass PCB with mounting holes to insert the rear jack terminals into, thus creating one board with up to 96 jacks soldered to it. The jacks must then all be screwed into a rack mount panel. The printed circuit board must also house a PCB mountable version of a desired interface of some kind, since an easier interface for the customer is the main point. Because the wirewrap terminals are in-line with the jack, the PCB plane is at 90 degrees to the jack, i.e. perpendicular to the longitudinal axis of the jack. A variation on this could be to have an individual PCB for each jack. Individual boards at 90 degrees to the jack is not positively known to have been tried. There are physical limitations that would make this difficult (space between jacks mounted in the jack-field).
2B. To overcom
Baker Daniel L.
Grant John E.
Armstrong R. Craig
AVP Mfg. & Supply Inc.
Duverne J. F.
Nguyen Khiem
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