The RJ-11 is mainly used to link telephone networks connector. It is small and has four contacts measures to support 4-way 2 cables. It is the most widely used globally for connecting conventional telephones, which generally tend to use only the two central threads to a single line or a twisted pair connector. And the four wires are used only for telephony equipment special using double line or two telephone pairs. After crimp the cable, it is almost impossible to disarm the RJ-11 without causing its deactivation.

When we talk about RJ45 ("Registered Jack" 45) we refer to a telecommunications network interface for wired connection of voice and data equipment.

This connector has 8 pins or connections and may have a specific category depending on the data transfer speed and bandwidth (category 5e, 6, etc.)

The common application is their use in Ethernet network cables under TIA/EIA-568-B standard that defines the arrangement of pins (pinout), but can also be used for other applications.

- Direct pin diagram:

EIA-568A
Pin No.1: WHITE-GREEN
Pin No.2: GREEN
Pin No.3: WHITE-ORANGE
Pin No.4: BLUE
Pin No.5: WHITE-BLUE
Pin No.6: ORANGE
Pin No.7: WHITE-BROWN
Pin No.8: BROWN

EIA-568B
Pin No.1: WHITE-ORANGE
Pin No.2: ORANGE
Pin No.3: WHITE-GREEN
Pin No.4: BLUE
Pin No.5: WHITE-BLUE
Pin No.6: GREEN
Pin No.7: WHITE-BROWN
Pin No.8: BROWN

- Schematic of crossed pins:

The crossover cable has one end with EIA-568A scheme and the other one with EIA-568B.

Depending on the quality and type, network cables are classified into categories that help us know the characteristics of them.

The categories of network cables most commonly used are:

- Category 5
- Category 5e
- Category 6
- Category 6
- Category 7

As can be seen, category 5e (enhanced or improved) and category 6A (Augmented), are an improvement of categories 5and 6, respectively, which it has improved the top speed and bandwidth.

The higher the category, the higher the speed of maximum data, the maximum 100 meters distance as its standard.

You can see a table which shows the 5 categories, where V is the maximum velocity, D is the maximum and MHz frequency which can work away.

Within the wide range of batteries on the market we can differentiate two large groups, disposable batteries and rechargeable batteries.
Disposable batteries are those that only allow a single use and when they are exhausted they can not be recharged. These batteries can store their energy for years.

Rechargeable batteries are those that can be recharged once exhausted. This type is losing charge when they are storedaccording to voltage. The most common we can find them of 1.2V and 3.7V

As a last point you have to take into account that lithium batteries, Lipo, Life etc. Due to its composition, specific loaders should be used.