Technically Speaking

The Personal Computer Memory Card International Association (PCMCIA) is an organization that is chartered with establishing, marketing, and maintaining a series of hardware and software standards for credit card-sized, integrated-circuit PC cards.

PCMCIA cards are your laptop’s mobile link to the outside world. You can use them to send last-minute data files from the airport to the office. Then you can link your laptop to connect to a branch office’s Ethernet port.

The PCMCIA standard specifies a removable device measur- ing 2.126" x 3.37" (5.4 x 8.6 cm)—basically the size of three stacked credit cards. PCMCIA cards have 68 pins and interface with both 8- and 16-bit buses. They also support physical access of up to 64 MB of memory.

PCMCIA cards provide universal expansion capability for laptop computers and personal digital assistants (PDAs). These tiny cards can support a wide variety of functions including faxmodem capabilities, mass storage, and memory extension for host machines.

PCMCIA enables you to choose the memory and I/O devices (LAN adapters, faxmodems, disk drives, etc.) that you need most. You are not restricted to using cards that work with only a specific computer make or model.

The three types of PCMCIA slots are defined by the thickness of the card that fits in them. All card types are backward compatible.

Type I cards are 3.3-mm thick. They’re used primarily in PD As as RAM, flash memory, electrically erasable programmable read-only memory (EEPROM), and one-time programmable memory (OTP).

Type II cards are 5-mm thick and are fully I/O-capable. You can use them for memory enhancements or for I/O features in modems, LAN connections, and host communications.

Type III cards measure 10.5-mm thick. They’re designed primarily for removable hard drives and radio communication devices that require a larger size. They can also be used for memory enhancements.

Type I and II extended cards are identical to the regular cards except they’re 50 mm longer. These cards are used in applications that need components outside of the systems or that simply need more room for internal components.

Plug PCMCIA cards into a host socket/adapter on the computer’s motherboard or connect them to its expansion bus. The socket side has the standard 68-pin interface for the card. The adapter side translates the PCMCIA interface signals to match the computer’s bus standards.

Socket Services 2.0 is the software interface between the card in the socket and the adapter to the computer’s bus. The standard Socket Services interface is what permits the use of any PCMCIA card on any PC equipped with a socket/adapter.

The programming interface for PCMCIA is called Card Services 2.0. It sends the signals to link Socket Services to the PC’s operating system and hardware.

Card Information Structure (CIS) contains information about how the card functions, its size, its electrical require- ments, and so on. On card insertion, the card passes this identifying information to the host system.

The system software reads the CIS data on insertion, installs the appropriate drivers, notifies relevant system resources, and initializes the card to make it available for use by the host.

There have been three major PCMCIA releases since the inception of the PCMCIA organization in 1989. PCMCIA Release 1.0 set the specification for a PC card, offering memory capabilities for mobile computing. Release 2.0 broadened the spec to include mass storage, modem, LAN, cellular and radio frequency communications peripherals. Release 2.1 enhanced the Card and Socket Services specs, and made improvements to the CIS. All standards are backward compatible.

7/13/2007

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Black Box RJ-11 manual Technically Speaking

RJ-11 specifications

The Black Box RJ-11 and RJ-45 connectors are essential components in modern telecommunications and networking, facilitating connectivity in both telephone systems and data networking environments. These connectors ensure reliable and efficient communication across various devices and networks, boasting a range of features and characteristics that cater to diverse requirements.

The RJ-11 connector is primarily used in telephony systems. Typically, it comprises a 6-position, 2-contact design, although it can also be found in 4- and 6-contact variants. The standard RJ-11 is compatible with telephone lines, allowing for easy connection of telephones, modems, and fax machines. Its compact size and simple design facilitate straightforward installation and replacement. The most notable feature of the RJ-11 is its ability to support voice transmission with a frequency range typically up to 1 MHz, which is adequate for standard phone conversations. The connector's design also minimizes interference and provides secure connections, enhancing call quality.

In contrast, the RJ-45 connector is widely recognized in networking applications, particularly Ethernet networks. This 8-position, 8-contact (8P8C) connector is fundamental for data transmission over Local Area Networks (LANs). The RJ-45 supports various Ethernet standards, including 10BASE-T, 100BASE-TX, and 1000BASE-T, allowing for data rates ranging from 10 Mbps up to 10 Gbps, depending on cable and equipment compatibility. One of the defining characteristics of the RJ-45 is its ability to accommodate shielded and unshielded twisted-pair cabling (STP and UTP), which helps reduce electromagnetic interference, thereby enhancing network stability and performance.

Both RJ-11 and RJ-45 connectors are designed for durability and longevity. They feature robust construction materials that resist wear and tear, ensuring consistent performance over extended use. Moreover, both connectors are easy to install and come with various cable assemblies and adapters to cater to different environments and requirements, providing flexibility and convenience for users.

As technology continues to evolve, the RJ-11 and RJ-45 connectors remain crucial in maintaining seamless communication and data transfer capabilities, serving as reliable interfaces in an increasingly interconnected world. With their distinctive features and reliable performance, these connectors will continue to play a vital role in both telephony and networking applications for years to come.