On a mobile phone, an expansion slot is an opening on the device that supports circuit boards, or cards, that give the phone added functionality. Memory cards, which give a mobile phone more data storage space, are the most common type of circuit board supported by mobile phone expansion slots, but others are supported as well. Memory cards come in a variety of capacities and sizes and are designed to work with most mobile phones.
Memory Cards
As of the date of publication, most mobile phones support Secure Digital, better known as SD, memory cards. Smartphones, such as the LG Optimus T, come with a limited amount of internal memory, making expanded memory an eventual necessity. Mobile phones accommodate the addition of memory through their built-in memory expansion slots. In the case of the Optimus T, which comes with just 170MB of internal memory, you can add microSD or microSDHC cards to the phone for up to 32GB of expanded memory.
SD Card Capacities
SD cards come in three categories: SD, SDHC and SDXC. Each category contains standard-, mini- and micro-sized versions, except for the SDXC category, which is only available in standard- and micro-sized formats. SD, miniSD and microSD cards offer up to 2GB of memory, while SDHC, miniSDHC and microSDHC cards provide between 2GB and 32GB of memory. SDXC and microSDXC cards are intended for use in high-end broadcast-quality video recorders and offer between 32GB and 2TB of memory.
USB Slots and Jacks
Another common form of mobile phone expansion slot is the USB slot, also known as a port. USB slots support USB buses which facilitate the transferring of data from the mobile phone to an external device (such as a personal computer) and vice versa. This type of interfacing requires the device with which the mobile phone is connecting to also have a USB port. USB 2.0 technology, which is the norm at the time of publication, is also able to transfer power between connected devices, making it possible to charge a mobile phone through its USB expansion slot while the connection is intact. Mobile phones commonly feature expansion slots that accommodate headphone jacks, which expand the phone's functionality if it is equipped with an audio player.
Miscellaneous
Due to the compact designs of the devices they're designed to be used in, such as cameras and mobile phones, SD cards are extremely small. For instance, SD, SDHC and SDXC cards are about the size of a postage stamp and measure 0.9 inch wide, 1.3 inches long and 0.1 inch deep. MiniSD and miniSDHC cards are about a third the size of SD, SDHC and SDXC cards, measuring 0.8 inch wide, 0.8 inch long and 0.1 inch deep. MicroSD, microSDHC and microSDXC cards are about the size of a fingernail and measure 0.4 inch wide, 0.6 inch long and 0.04 inch deep. Mobile phone manufacturers build memory card expansion slots into the interior of the device to protect the expansion device's fragility.
Tags: mobile phone, expansion slots, cards about, inch deep, inch wide