Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!ihuxz!parnass From: parnass@ihuxz.UUCP Newsgroups: sci.electronics Subject: Re: FCC req for electronic kits (limits & such) Message-ID: <2438@ihuxz.ATT.COM> Date: Fri, 20-Nov-87 10:06:43 EST Article-I.D.: ihuxz.2438 Posted: Fri Nov 20 10:06:43 1987 Date-Received: Sun, 22-Nov-87 06:11:17 EST References: <1080@raybed2.UUCP> <2035@umd5.umd.edu> <19164@amdcad.AMD.COM> <221@scdpyr.UUCP> Organization: AT&T Bell Laboratories - Naperville, Illinois Lines: 95 x Herb Poppe asks questions about FCC Part 15 standards: | 1) Is every "device" used in the home that contains a "computer" (micro- | processor, microcontroller, etc.) consider a "Class B computing device"? | Is that fancy microwave oven, washing machine or toaster(?) containing | a single-chip micro have to be certified by the FCC? If not, what are | the rules associated with allowing such devices to be exempted. Yes, those fancy home appliances that use microprocessors as control elements are computing devices if they meet FCC's definition. FCC Part 15J (Technical Standards for Computing Equip- ment) defines a COMPUTING DEVICE as any electronic device or system that generates and uses timing signals or pul- ses at a rate in excess of 10,000 pulses (cycles) per seconds and uses digital techniques. A CLASS A device is a computing device that is marketed for use in a commercial, industrial, or business environ- ment. A CLASS B device is a computing device that is marketed for use in a residential environment notwithstanding its use in commercial, business, and industrial environment. Class B standards for radiated are stricter than Class A. | 2) A micro is just a (relatively) high speed digital circuit. Certainly | other high speed digital circuits that are not "computers" also generate | RF energy that could interfere with radio/TV reception. If such circuits | appear in products used in the home must they be certified as Class B | computing devices? If so, what is considered "high"? The rules apply to end products and peripherals (I/O dev- ices), not to subassemblies and components. TABLE 1. FCC Part 15 Subpart J Limits for Radiated Emis- sions _________________________________________________ | | Class A Class B | | Freq(MHz) Dist(m)| uV/m uV/m uV/m uV/m| |____________________|___________________________| | 30-88 3 | 300 49.5 100 40 | | 88-216 3 | 500 54 150 150 | | 216-1000 3 | 700 56.9 200 46 | | | | | 30-88 30 | 30 29.5 | | 88-216 30 | 50 34 | | 216-1000 30 | 70 36.9 | |____________________|___________________________| If the device is connected to an AC power line, it must also meet FCC standards for conducted emissions. TABLE 2. FCC Part 15 Subpart J Limits for Conducted Emis- sions __________________________ | Class Freq(MHz) uV | |_________________________| | A 0.45-1.6 1000| | 1.6-30 3000| | | | B 0.45 30| |_________________________| | 3) How is the "hobbyist" affected by the rules? Can I "homebrew" a system | and be legal? If so, can I make systems for my friends? | Can I describe such a system in the hobby press and be | legal? If so, can I offer "kits" for the described project at cost? for a | profit? FCC rules don't specify what articles you can write in the hobby press. If you offer "kits" for sale, they must comply with the FCC Part 15. Keep in mind that even if a device complies with Part 15 standards, but still causes harmful interference, the user may be required to stop operation. -- ===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-=== Bob Parnass, Bell Telephone Laboratories - ihnp4!ihuxz!parnass - (312)979-5414