Talk:MHP to laptop interface possibility

I don't think this idea will go very far --- MHP applications are downloaded by the video distributor (cable or satellite), who have little interest in working with any computer manufaturer. What information were you hoping to transfer over the telephone port? The meta information about the video content is multiplexed with the video, and doesn't require MHP to acquire.

I am thinking that the MHP broadcasting system could be used to deliver software and data to the laptop over a terrestrial or satellite broadcasting system. The idea is (was?) to use the telephone port to pass the software and data from the broadcast stream to the OLPC laptop. The telephone port connection link would only be within the same room. I was thinking that it might be possible to use that telephone port as a way to use ordinary MHP set-top boxes for the OLPC project without needing to get special MHP equipment made. If special MHP reception equipment which can link directly into the laptop without needing to use the telephone port exists or can be built, then great; using the telephone port can then be discarded as an iterim idea for how to try to get things moving with what equipment could potentially be obtained at present as far as I knew at the time.

A more likely role for MHP in OLPC is to allow laptop users to run the interactive applications from video distributors. A DVB receiver now fits in a USB dongle. With a little software, the XO becomes a full fledged interactive DVB-MHP enabled digital set top box --- with about twice the horsepower of most STBs on the market. It can use the WiFi connection for uplink, such as audience voting in shows. I may be being too judgemental, but I haven't seen or heard of any MHP applications which would make this effort worthwhile! ---Wad 23:38, 28 January 2007 (EST)

Well, there may well not be any existing MHP applications which would make this effort worthwhile. The idea is to use the MHP broadcasting technology, which exists, as a way to deliver software and data to the laptops. The software and data would be originated from within the OLPC project. There may be vast areas of the developing world where there is no internet connection available over telephone lines. If there could be a reception-only satellite reception dish at a rural school and software and data, broadcast continuously as an MHP service, could be received by selectively gathering information from the MHP service, then loaded into one laptop attached to the MHP reception system, then the children could receive lots of software and data over the local laptop wireless network. I am not envisaging using the uplink capabilities of MHP at all, just the reception part.

MHP has at the heart of it my telesoftware invention: telesoftware does not use a telephone line at all but works by the unidirectional cyclic broadcasting of software and its selective use by reception-only advanced television systems. MHP calls this enhanced television and then uses the term interactive for systems which use an uplink as well, even though the uplink need not go back to the central broadcasting computer but could go somewhere else entirely, such as, say, a mail-order clothing business in order to process an order. So, in my opinion, the MHP specification, by the parlance which it uses, greatly underestimates the potential interactive capabilities of the one-way broadcasting of software.

Certainly, in theory my telesoftware invention could be used for the OLPC project without having anything to do with the DVB system or MHP at all. It is a matter, however, of using the most convenient and practical available infrastructure. The first telesoftware broadcasts used teletext broadcasts, lines of digital information within a few of the unused lines on 625-line analogue television channels. That was because teletext pages were already being broadcast. In fact, I invented telesoftware in the autumn of 1974 before I was aware of the existence of teletext. I had originally thought that separate broadcasting channels would be needed. When I learned of teletext later that year I realized that teletext pages could provide a way of implementing telesoftware broadcasts without needing additional broadcasting channels. Telesoftware was invented as an extension to broadcasting of a theoretical method of function generation for an analogue-hybrid computer where information would be sent unidirectionally by wire to any number of function generators within an analogue-hybrid computer: telesoftware thus came from outside the broadcasting industry. The idea for the analogue-hybrid function generator was based upon an analogue function generator which was in the literature of analogue computing. In that original, if I remember it correctly, an analogue signal, such as, for example, a sine wave was sent continuously along the wire. A second wire carried a sawtooth wave at the same frequency, synchronized as to phase. An analogue computer function generator wishing to compute a value y = sin(x) from a voltage x, x being quasi-static in relation to the sine wave and sawtooth signals , would compare the value of x with the value of the sawtooth wave and then do a sample and hold on the sine wave when the value of x and the value of the sawtooth signal were the same. Thus the value of y would be linear to sin(x) so scaling y and maybe adding or subtracting a constant to of from it would produce the desired value. I seem to remember reading that that would work well if the frequency of the sine wave and the sawtooth wave were at least one hundred times the frequency of x. In practice this was easily achieveable as x would typically be slow-moving.

So, today, in practice, for long distance broadcasting using a satellite system, DVB-MHP is probably the best system to use as the carrier. I know only a little about the practicalities of implementing what I am suggesting and that is mostly theoretical rather than practical experience. Yet, if you and others can implement my idea then maybe the laptops can use my telesoftware invention for education.

---

There is now a mention of the article page in the following thread in the Consumer and Commerce - Java TV forum of the Sun Developer Network.

http://forum.java.sun.com/thread.jspa?threadID=5209024