EXTENDED PC CARD TYPE III SLOT

Publishing Venue

Motorola

Related People

Abstract

PC card ports are integrated into more and more portable computing devices as more types of memory and I/O PC cards are being developed and offered for sale. There are two basic types of PC card ports, the Type I/II (which holds either a Type I or Type II card and is 5.5 mm thick), and the Type III port which is u.sually configured to hold one Type 111 card or two Type I or II cards (this port is 11 mm thick). PC card Type III ports require the use of significant volume within their host device-basically twice the volume versus a single Type I/II port. This volume can amount to as much as twenty-five percent of the volume for a handheld host device. Moreover, a significant percentage of consumers may never have the need for a Type III port, and they may not want to carry a host device that is "oversized" due to a feature for which they have no use.

MO-LA Technical Developments

EXTENDED PC CARD TYPE III SLOT

by Hal Gomnz and Bob Uskali

BACKGROUND

  PC card ports are integrated into more and more portable computing devices as more types of memory and I/O PC cards are being developed and offered for sale. There are two basic types of PC card ports, the Type I/II (which holds either a Type I or Type II card and is 5.5 mm thick), and the Type III port which is u.sually configured to hold one Type 111 card or two Type I or II cards (this port is 11 mm thick). PC card Type III ports require the use of significant volume within their host device-basically twice the volume versus a single Type I/II port. This volume can amount to as much as twenty-five percent of the volume for a handheld host device. Moreover, a significant percentage of consumers may never have the need for a Type III port, and they may not want to carry a host device that is "oversized" due to a feature for which they have no use.

PROBLEM

  The dilemma for the device manufacturer is whether to integrate the Type III port and add significant size to the device, or forego the port and exclude consumers from peripheral products that are only available in the Type 111 format. This dilemma can also adversely affect the Type III PC card manufacturers if the host device manufacturers decided they cannot afford to tit the Type III port in the device.

  Another potential problem with PC cards is providing adequate EMI/RFI shielding between the host device and the card, as well as between the card and the immediate environment. Depending on the type of card used and the type of host device, shielding may or may not be necessary. However, if shielding is necessary, isolating the PC card from the rest of the host device and the combination from the environment can be extremely difftcult for most

PC card ports due to the geometry and opening required to insert and remove the card(s). The dilemma here is whether or not the device manufac- turer should add the cost of shielding that may not be necessary for every consumer, or create a design that provides effective and inexpensive shielding.

SOLUTION

  Refer to Figure 1. A solution to these problems is to locate a PC card Type I/II slot adjacent to an exterior surface of the host device and use a removable and replaceable door as the adjacent exte...