lenny@helm.UUCP (Lenny Tropiano) (07/02/86)
H E L P!
We are developing software for AT&T series computers. At this time
we want to make a demonstration video tape ("how-to-do") but are running
into some stumpling blocks. Video cameras don't have a high enough
resolution to record from a monitor. Is it possible to record directly
from a AT&T system directly (without camera) to VCR?
We had an idea to use the "9-pin" output from our PC6300. Unfortunately
we do not have the technical specs for what that port sends out. Does
anyone have such a pinout diagram? Does it in fact actually give us
video output? In theory we should be able to make a cable from 9-pin
male to RCA jack, right?
Please respond to either: ..philabs!sbcs!helm!lenny
-or-
American LP Systems, Inc.
1777 Veterans Highway
Islandia, New York 11722
-or-
(516) 582-5525 (call collect if
necessary)
Thank you,
Lenny Tropianosandersr@ecn-pc.UUCP (Robert C Sanders) (07/10/86)
In article <527@helm.UUCP> lenny@helm.UUCP (Lenny Tropiano) writes: > > H E L P! > >We are developing software for AT&T series computers. At this time >we want to make a demonstration video tape ("how-to-do") but are running >into some stumpling blocks. Video cameras don't have a high enough >resolution to record from a monitor. Is it possible to record directly >from a AT&T system directly (without camera) to VCR? > > Lenny Tropiano AT&T makes just the exact hardware you require!! We too are trying to do exactly the same thing -- in a different way. Our requirements are to send an EGA compatible output into an RS170A video mixer (standard NTSC color composite video). NOBODY in the computer world recognizes the broadcast standard for video is THE standard. IBM was the first to be different (really Apple was, for purely economic reasons, IBM for political reasons). The industry standard (real industry!! Broadcasting) does have a standard: the analog RGB standard, good for about 6 MHz or so. IBM compatible machines, of which 6300 is (I know I will get flamed for that one!), separate the composite sync into separate hori-sync, and vert-sync. The RS170 standard states levels at 0 to 0.714 volts -- not like the TTL 0.4 to 3.8 volts. The standard also states the sync frequency to be 15.75 Mhz. IBM's crystal runs at 14.77 MHz. Generally, with input buffers, the IBM parameters were *GOOD ENOUGH* to work with most monitors on the market. Note that the monitors are operating within marginal spec; there's no way a tape recorder requiring proper levels and frequencies can even accept an analog RGB from a 6300 or any IBM compatible. AT&T markets a series of Extremely-High Resolution graphics boards for both in-coming (digitizing) and outgoing Analog RGB video. *THEY* decided to go with the industry standard in that respect anyhow. But they still use the on-board frequency. They also market a Composite Video Adaptor that plugs into a 6300 (or IBM compatible), and converts in-coming composite-color-NTSC video into Analog RGB, and Analog RGB into NTSC color-composite video output -- suitable for videotape recording. Their high-res board will syncronize with the incoming video, as well as the adaptor board, so sync'ing is not a problem -- with their hardware and software (only AutoCad supports them outside of AT&T). If you want to record standard CGA or EGA video in a deck, you will have to do a lot of kludging to existing video cards to sync up properly, and then build a circuit that will combine IBM-style TTL RGB into 3-color (IBM has separate INTENSITY AND SUB_INTENSITY signals) RGB, and also to knock down the voltage from TTL to 0.714 volts. After all of that, then the AT&T board will generate a signal suitable for taping. "Seems like a lot to go through," you say. You're right. "Somebody should make something like this." You're right. "The market is too small for computer peripheral people to bother." You hit the nail on the head! Not to mention that most electronic engineers at computer peripheral places know nothing about real-world electronics -- what the world already has set up in other fields sometimes related to the computer industry -- only just. - bob -- Continuing Engineering Education Telecommunications Purdue University ...!ihnp4!pur-ee!pc-ecn!sandersr "Reject, Resound, Rejoice! -- who needs them!" -- me (bob) Let's make like a BSD process, and go FORK-OFF !!