PC Card (PCMCIA) form factors: A PCMCIA card measuring 10.5 mm in thickness belongs to which type classification?

Introduction / Context:
Older laptops used PCMCIA (PC Card) slots that accepted several card thicknesses for modems, network adapters, flash storage, and miniature hard drives. Knowing the correct type prevents damage and ensures the right device is used in the correct bay.

Given Data / Assumptions:

• The card thickness is specified as 10.5 mm.
• We are classifying the PCMCIA type by physical thickness only (not function).
• All types share the same edge connector but differ in mechanical height.

Concept / Approach:
PCMCIA defines three common card heights: Type I is 3.3 mm (usually memory), Type II is 5.0 mm (typical for modems and NICs), and Type III is 10.5 mm (accommodates miniature hard disk drives or devices needing more vertical clearance). Therefore, a 10.5 mm card corresponds to Type III.

Step-by-Step Solution:

Verification / Alternative check:
Service manuals often state that a Type III bay may occupy the space of two adjacent Type II slots; visual inspection shows a deeper cage for Type III devices such as PC Card hard drives.

Why Other Options Are Wrong:
Type 1 and Type 2 are too thin. 'Type 1 and 3' is not a single, valid classification. 'None of the above' is invalid because Type 3 is correct by standard definition.

Common Pitfalls:
Attempting to insert a Type III card into a laptop that only supports Type I/II can jam or damage the eject mechanism. Conversely, assuming electrical incompatibility when the issue is purely mechanical can lead to unnecessary replacement of functional cards.

Final Answer:
type 3