Pub. 42004-462C
Models 13382 WiFi and 13383 VoIP Addressable Amplified Speakers Page 3 of 24
P:\Standard IOMs - Current Release\42004 Instr. Manuals\42004-462C.docx
09/18
Safe Handling of CMOS Integrated Circuit Devices
Many integrated circuit devices used in communications equipment are CMOS (Complementary Metal
Oxide Semiconductor) type devices. Because of their high open circuit impedance, CMOS integrated
circuits are vulnerable to damage from static charges. Care must be taken when handling, shipping, and
servicing them and the assemblies in which they are used.
Even though protection devices are provided in CMOS integrated circuit inputs, the protection is effective
only against overvoltage in the hundreds of volts range such as is encountered in an operating system. In
a system, circuit elements distribute static charges and load the CMOS circuits, decreasing the chance of
damage. However, CMOS circuits can be damaged by improper handling of the modules, even in a
system.
To avoid damage to circuits, observe the following handling, shipping, and servicing precautions:
1. Prior to and while servicing a circuit module, particularly after moving within the service area,
momentarily touch both hands to a bare metal, earth-grounded surface. This will discharge any static
charge that may have accumulated on the person doing the servicing.
NOTE:Wearing a conductive wrist strap will minimize static build-up during servicing.
2. Whenever possible, avoid touching any electrically conductive parts of the circuit module with your
hands.
3. Power down the unit before installing or removing the circuit module.
4. When servicing a circuit module, avoid carpeted areas, dry environments, and certain types of
clothing (silk, nylon, wool, etc.) because they contribute to static build-up. Similarly, disconnect the
test probe prior to removing the ground lead.
5. All electrically powered test equipment should be grounded. Apply the ground lead from the test
equipment to the circuit module before connecting the test probe.
6. If a circuit module is removed from the system, it is desirable to lay it on a conductive surface (such
as a sheet of aluminum foil) which is connected to ground through 100 kilohms of resistance.
7. When soldering, be sure the soldering iron is grounded and has a grounded tip.
8. Prior to connecting jumpers, replacing circuit components, or touching CMOS pins (if this becomes
necessary in the replacement of an integrated circuit device), be sure to discharge any static build-up
as described in step 1. Since voltage differences can exist across the human body, it is recommended
that only one hand be used if it is necessary to touch pins on the CMOS device and associated board
wiring.
9. When replacing a CMOS integrated circuit device, leave the device in its conductive rail container or
conductive foam until it is to be inserted into the printed circuit module.
10. All low impedance test equipment (such as pulse generators, etc.) should be connected to CMOS
device inputs after power is applied to the CMOS circuitry. Similarly, such low impedance
equipment should be disconnected before power is turned off.
11. Replacement modules shipped separately from the factory will be packaged in a conductive material.
Any modules being transported from one area to another should be wrapped in a similar material
(aluminum foil may be used). Never use non-conductive material for packaging these modules.
