HP 8921A Programmer's Manual page 6

WARNING:
Product Markings
Always use the three-prong ac power cord supplied with this product. Failure to
ensure adequate earth grounding by not using this cord may cause product damage.
This product is designed for use in Installation Category II and Pollution
Degree 2 per IEC 1010 and IEC 664 respectively. For indoor use only.
This product has autoranging line voltage input, be sure the supply voltage
is within the specified range.
To prevent electrical shock, disconnect instrument from mains (line) before
cleaning. Use a dry cloth or one slightly dampened with water to clean the
external case parts. Do not attempt to clean internally.
Ventilation Requirements: When installing the product in a cabinet, the
convection into and out of the product must not be restricted. The ambient
temperature (outside of the cabinet) must be less than the maximum
operating temperature of the product by 4° C for every 100 watts dissipated
in the cabinet. If the total power dissipated in the cabinet is greater than 800
watts, then forced convection must be used.
CE - the CE mark is a registered trademark of the European Community. A
CE mark accompanied by a year indicated the year the design was proven.
CSA - the CSA mark is a registered trademark of the Canadian Standards
Association.
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