Switchcraft EH Series Audio/Video/Data Connectors Now Available In New Zealand

Back about two years ago when we were fully in the swing of installing projectors in our classrooms, I had to come up with a scheme for getting wall plates in for the VGA cables that connect projectors and laptops. Up until now all that has been available or easy to find has been a PDL or HPM plastic wallplate that can have a butchered plug screwed to it (see the series of articles here: parts 1, 2, 3, 4). There are some other brands of wallplate becoming available with different combinations of VGA adaptor and other connectors, but they are still hard to find, and some of them require the cable to be connected as bare wire ends (which is very fiddly to do with a wallplate, because you need some way of securing the cable to the plate to stop from breaking the wires off).

Switchcraft is a US manufacturer well known in the professional audio industry for their high quality connectors (XLR and others) and their approach to this market has been to develop the EH Series, which is a range of different types of audio, video and data connectors. Most of the audio/video connectors are of the feedthrough type, which is designed to be connected with a plug on both sides. They are very easy to install like this because there is no need to strip and solder wires onto terminals. As we prefer to install VGA cables that already have plugs fitted, the feedthrough suits our requirements perfectly as we just need to screw the plug directly onto the feedthrough and install it into a wall plate. The EH Series are particularly notable in that they are designed to fit within the profile of a standard panel mount XLR connector, and thus the inserts will fit into a wide existing range of panels already manufactured for the professional audio industry.  Switchcraft product is now handled in New Zealand by Jansen Professional Audio, who can also supply the various panels and have recently begun to bring in small quantities of EH Series connectors; if there is not one listed on their website that you want, they may be able to order in other types. For a wall mount scenario have a look at this type of plate which is one of an extensive range they carry to handle various different situations. Jansen give substantial discounts to schools so these products are well worth looking into, particularly for control rooms and other situations where you may want to install these connectors into panels with other types.

Electrical safety standards falling

This photo is of the inside of a well known and supposedly high quality (Australian) brand of plugbox which I would have unhesitatingly recommended to anyone until recently. Observe the earth contacts on the two left hand sockets, which have a much wider gap than the two on the right. The left hand pair are in fact not making contact with the earth pin on any standard 3 pin plug and this came to notice because the plugbox failed when connected for testing in a Portable Appliance Tester. This plugbox is less than a year old and the two left sockets would have each done less than 100 insert/removal cycles.

Since I have many older plugboxes which have withstood considerably more cycles and are more robustly built (yet were not expensive in their day) I asked the authorities in this country why this design was allowed to be sold in New Zealand and pass our national electrical safety certification standards. Their only response is that “these products are not designed for this type of use”. To which I would ask “why not”? Effectively what we are told is that it is acceptable to sell a plugbox that is designed and built so cheaply that the integrity of the safety earth cannot be guaranteed. Here in words is the requirement of the safety standard: “In New Zealand (and Australia) the EPOD is a declared article, requiring formal approval by the electricity Regulator before legal sale. In order to gain approval, each model of EPOD is tested and inspected to a specific AS/NZS safety standard that a New Zealand and Australian committee of industry experts and Regulators have produced to ensure that EPODs are safe to use.” If the above is an indication of what is required to pass this standard then it is very poorly written or does not mandate durability. Probably this is in part because the standard does not mandate sufficiently a minimum standard of construction.

As the public at large would not have access to Portable Appliance Testers most people would be unaware that a plugbox which is by all appearances in good condition, could have sustained internal damage that renders the integrity of the safety electrical earth invalid. If that is the case then why are there any requirements for the design of plugs and sockets in relation to the earth pin and earthing as safety mechanisms for appliances? The failure of this plugbox was detected as part of an inspection and testing regime for New Zealand schools that is mandated by the Ministry of Education. It appears there would be a strong case to advise schools that these devices must be considered failure prone and potentially unsafe with a short working life.

Offline Files in Windows 7

Offline Files is a technology that was first introduced in Windows XP. And it was pretty much of a dog back then. We did experiment with getting some laptop users to have it running, because we hoped it was going to make automated backups of their stuff. The problem with the earlier versions of Offline Files are things like, if the server got changed around, Offline Files stopped working. Not long after we started testing, we changed from a Linux Samba DC to a Windows DC. That was the end for Offline Files because there was no obvious way to tell it how to change the location of where the files were, or to sync its existing cache to a new location, or something. There were other problems as well, but I’ve forgotten, however I think it gained a certain unenviable reputation in the industry, and my response to it was to configure a group policy for our whole domain to disable it.

In Windows Vista, Offline Files became part of the Sync Center and this has continued in Windows 7. We didn’t have enough laptops running Vista to get around to trying out OF before we started moving to 7, and then I was advised that OF has become a “mature product” in 7, worth implementing for that backup type of system again. So that is what we are doing. In order to get the best out of OF and especially with a laptop that is connecting to a server, I am setting up new Group Policy objects for folder redirection and OF settings. The user’s Documents folder will be redirected to the server and automatically cached by OF, but their Pictures, Videos, Music and Downloads folders will be redirected to the local profile so that these bulky items don’t consume sync bandwidth or server space. Folder redirection is per-user, but in order to ensure that it only applies to specific computer usage (i.e. Windows 7 laptops), it will be configured as a loopback policy. OF settings is either per-computer or per-user, and in this case it will be configured per-computer.