EMUSIC-L Digest Volume 46, Issue 06 This issue's topics: LAPC etc. LAPC-1 MCB-1 (10 messages) Your EMUSIC-L Digest moderator is Joe McMahon . You may subscribe to EMUSIC-L by sending mail to listserv@american.edu with the line "SUB EMUSIC-L your name" as the text. The EMUSIC-L archive is a service of SunSite (sunsite.unc.edu) at the University of North Carolina. ------------------------------------------------------------------------ Date: Mon, 9 Nov 1992 15:46:35 CST From: GE2516@SIUCVMB.SIU.EDU Subject: LAPC etc. I'm no expert, but I believe the LAPC is an MT32 on a PC card with an MPU401 interface. I'm sorry I can't help any further--anyone else have any ideas? Eric Nielsen GE2516@siucvmb.siu.edu University Electronic Southern Illinois University Communications at Carbondale ------------------------------ Date: Mon, 2 Nov 1992 09:05:15 CST From: "(Michael Colicos)" Subject: LAPC-1 MCB-1 Does anyone know the pin assignments for the d_sub connector on the LAPC-1? As a guitarist I never got the DCB-1 midi connector box, but I now want to connect an old midi keyboard that I just picked up. Having to now pay another $100+ for an 'adaptor' stinks of a marketing move to me, so I want to try and wire my own. Thanks. Michael Colicos mcolicos@nba19.med.uth.tmc.edu ------------------------------ Date: Mon, 9 Nov 1992 13:59:39 EST From: ronin Subject: Re: LAPC-1 MCB-1 i don't know what the LAPC-1 is, but if the DCB connector that you refer to is part of Roland's old communication standard, you can forget just wiring a midi-dcb interface yourself. midi is a serial data communications standard entirely distinct from the parallel mechanism developed by roland for its dcb system. you'd need to capture, translate, and re-emit the data, requiring at least a small microprogrammed processor. -----------< Cognitive Dissonance is a 20th Century Art Form >----------- Eric Harnden (Ronin) or The American University Physics Dept. 4400 Mass. Ave. NW, Washington, DC, 20016-8058 (202) 885-2748 ---------------------< Join the Cognitive Dissidents >------------------- ------------------------------ Date: Tue, 10 Nov 1992 13:07:00 +0800 From: H8710244@HKUCC.HKU.HK Subject: Re: LAPC-1 MCB-1 e is no processor inside. I am B. Sc. in Electronic Engineering. I am confident of it. from, Roland h8710244@hkucc.hku.hk ------------------------------ Date: Tue, 10 Nov 1992 07:50:45 CST From: "(Michael Colicos)" Subject: LAPC-1 MCB-1 The LAPC-1 is advertized as a MT32 and a MPU401 on a card. I bought one figuring it was cheaper than getting the two units separately. I didn't have an immediate use for the MPU401, so when I read in the "manual" that I would need an extra connector, the MCB-1 to use the MPU401, I didn't buy one and figured it was an inexpensive adaptor of some sort. After picking up an old midi keyboard, I checked the price and it's $150 from Roland! As you can buy an MPU401 cheaper than that, I was quite dismayed, and sent the original message out about wiring it yourself. Since then this is what I've learned. Of the 5 MIDI pins, 2 and 4 (going clockwise) carry the serial MIDI data, and 3 connects to the shield. The LAPC-1 has a DB-15 joystick style connector. An hour of experimentation found the following 2 - X X X X X X X X X X X X - 4 X X X This results in a fully functional link between my keyboard and the MPU401. I am sure this is not blessed by Roland, and I have no idea whether or not it can harm the LAPC-1, but it does work. And it beats dropping another $150. ------------------------------ Date: Tue, 10 Nov 1992 08:01:04 CST From: "(Michael Colicos)" Subject: Re: LAPC-1 MCB-1 Yes, I believe the IC's you get are for ..... the metranome! ------------------------------ Date: Tue, 10 Nov 1992 22:06:00 +0800 From: H8710244@HKUCC.HKU.HK Subject: Re: LAPC-1 MCB-1 Do you mean that you just connect the cables and no electronic component? ------------------------------ Date: Tue, 10 Nov 1992 08:16:42 CST From: "(Michael Colicos)" Subject: Re: LAPC-1 MCB-1 Well, since my keyboard sits 4 feet from my computI guess thats why I have no problems. I have no plans to go on the road with this equipment, so I'll stick to my cheap setup. ------------------------------ Date: Tue, 10 Nov 1992 22:17:00 +0800 From: H8710244@HKUCC.HKU.HK Subject: Re: LAPC-1 MCB-1 No, the IC is not for metranome. ------------------------------ Date: Tue, 10 Nov 1992 22:18:00 +0800 From: H8710244@HKUCC.HKU.HK Subject: Re: LAPC-1 MCB-1 One IC is used for strengthen the signal and one to prevent shortage if the computer and the MIDI device have got different grounds. ------------------------------ Date: Thu, 12 Nov 1992 11:33:02 MET From: cgra@BTMA74.DNET Subject: RE: LAPC-1 MCB-1 You should really have an opto-isolator on the circuit somewhere: +--------+ ----->-------+-+ +-+----->--- 300 mA(?) ! ! -> ! ! ------<------+-+ +-+-----<--- +--------+ opto-isolator The o-i serves both to prevent the whole midi rig from becoming a huge aerial to pick up all the electical noise in the joint, and to electically isolate the various instruments from eachother, reducing the incidence of "fried musician syndrome". Probably neither really counts in your case, but it's worth knowing. ------------------------------ End of the EMUSIC-L Digest ******************************