domingo, 1 de mayo de 2011

Comic que enseña a soldar.

Este comic enseña a soldar componentes electrónicos. Muy bueno.


Comic_Soldar_Es_Facil_Spanish_Final.pdf

jueves, 16 de diciembre de 2010

Freedwgviewer visor de archivos autocad.

Freedwgviewer, es un programa gratis que permite ver archivos formato autocad (dwg). Permite encender apagar layers, imprimir selecciones de un plano, tiene herramientas de medición, etc. Muy recomendable.

Se puede descargar de http://www.bravaviewer.com

lunes, 22 de noviembre de 2010

Redes Locales (LANs)

Características:
-Baja tasa de error
-Uso de canales de alta velocidad
-Escaso tiempo de propagación de la señal
-Se construyen sobre cable privado
-Fácil de compartir recursos de alta eficiencia
-Comunicaciones cliente servidor (servicio de correo, nombres, fiscos)
-Comunicación distribuida peer to peer
-Simplifica conectividad con otras redes.

Ejemplos
-Ethernet 802.3
-Token Ring 802.5
- Fast Ethernet 802.3
-100 VG: 802.12
-ATM Lan E





IEEE 802


Grupos de Trabajo

Redes Metropolitanas (MANs)

Características:
-Baja tasa de error
-Uso de canales de alta velocidad
-Tiempo de propagación de la señal regular a bajo
-Cable privado o arrendado (utiliza espacios públicos)
-Fácil compartir recursos con alta eficiencia
-Comunicación distribuida (peer to peer) 

Ejemplos:
-FDDI
-DBDB (Con transporte SMDS)
-ATM

Ref: DQDB
-In telecommunication, a distributed-queue dual-bus network (DQDB) is a distributed multi-access[disambiguation needed] networkthat (a) supports integrated communications using a dual bus and distributed queuing, (b) provides access to local or metropolitan area networks, and (c) supports connectionless data transferconnection-oriented data transfer, and isochronous communications, such as voice communications.

IEEE 802.6 is an example of a network providing DQDB access methods.
FDDI
Fiber Distributed Data Interface (FDDI) provides a 100 Mbit/s optical standard for data transmission in a local area network that can extend in range up to 200 kilometers (124 miles). Although FDDI logical topology is a ring-based token network, it does not use the IEEE 802.5 token ring protocol as its basis; instead, its protocol is derived from the IEEE 802.4 token bus timed token protocol. In addition to covering large geographical areas, FDDI local area networks can support thousands of users. As a standard underlying medium it uses optical fiber, although it can use copper cable, in which case it may be refer to as CDDI (Copper Distributed Data Interface). FDDI offers both a Dual-Attached Station (DAS), counter-rotating token ring topology and a Single-Attached Station (SAS), token bus passing ring topology.
FDDI was considered an attractive campus backbone technology in the early to mid 1990s since existing Ethernet networks only offered 10 Mbit/s transfer speeds and Token Ring networks only offered 4 Mbit/s or 16 Mbit/s speeds. Thus it was the preferred choice of that era for a high-speed backbone, but FDDI has since been effectively obsoleted by fast Ethernet which offered the same 100 Mbit/s speeds, but at a much lower cost and, since 1998, by Gigabit Ethernet due to its speed, and even lower cost, and ubiquity.