Analog Modems
Are devices that convert digital signals into a computer's analog telephone signal and vice versa, allowing computers to transmit and receive information by conventional telephone line. The chips are performing modulation and demodulation functions are almost standard, so the differences between one or the other modem is the only type of housing or other electronic elements that compose it.
The speed of analog modems ranging from 9.6 Kbps to 56 Kbps, for example the transfer time of a file of 10 Mb ranges from 23 hours to 24 minutes, respectively.
Within the analog modems are distinguished internal and external modems modems. In addition there are two types of analog modems that fit within the domestic rate, but because of its particularity is treated separately: HSP modem or software modem and PC Card.
External Modems
They are placed on the desk along with our team, box-shaped and are connected by a telephone line side to the other side to the computer. The advantage is that they are portable and modem status is known at a glance (marking, no / line, passing, etc..) Due to that most clearly presented in the front.
Serial Port. Are the oldest and, today, are being replaced by USB. The important thing is that this port should be set at maximum speed. Its main drawback is that take up space and need a significant source of additional power, but the big advantage is that all computers have serial ports, so they are very compatible.
USB (Universal Serial Bus). Connection and setup are simple. They share the port with other devices, but most do not require a power source. Occupy approximately the same space for a serial port.
Internal Modems
Shaped card (she is ready on the different components of the modem) and placed in so-called expansion slots. To be connected directly into the computer, only have an external output for connection to a phone line.
ISA slot. Due to the low speeds involved in these devices, are now virtually obsolete, although for many years was used exclusively.
PCI slot. Is the most common at present. Is automatically configured and is a less workload for the CPU of the computer. The modem you use this slot, they are inexpensive.
AMR slot. They are found only in some very modern plates, but are not recommended because of its low yield. Make the processor do all the work. Today, they are no longer in use.