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Pankaj's BlogProject Manager ( Database Specialist )
July 25 Make a CAT5 IntercomIt has been over a century and a half since Alexander Graham Bell whispered the words ‘Mary had a little lamb’ and changed the way mankind communicated. Modern life is unimaginable without a telephonic device—be it a sophisticated cell phone or an archaic pulse dial telephone still in use in certain parts of India. If you have gone fully digital, don’t thrown out your land line instruments in a hurry. This workshop will help you make a functional small distance intercom device.
A straightforward way to build a simple intercom at home is to use two old land line telephone handsets, run a wire between them and apply some power. An improvised circuit can include a buzzer at both ends, so that the person at the other end can be alerted to pick up the phone. First of all, you need to decide which rooms you will install the intercom. Then you need to collect all the materials listed on this page before getting down to work.
There are different ways to power the circuit. The first is to simply use a 9V battery. However, the downside to this option is that battery will drain out in no time leaving the intercom connection dead. Alternatively, you can power the circuit using any good pure 12 V DC power adapter. Any laptop’s idle or unused power adapter is the best choice. Don’t worry if the voltage level isn’t exactly 9 V—anything with an output voltage below 24 V will do the job. Note that the intercom needs to be powered at one end of the circuit only.
The scenario for which we designed and built this intercom included two rooms having computers connected over a network CAT5 cross-cable. Since a network cable consists of four pairs of wires, of which only two pairs are used by the network adapter, the other two unused pairs were perfect for our purpose. We only require four wires for the intercom to function, so if you don’t already have a network cable connecting computers between floors or rooms, you can use any ordinary telephone cable with four cores or two pair wires.
Construction
If you plan on using an existing network cable, (like in our workshop), note that pins one, two, three, and six (from the RJ45 connector) are used by the network adapter while the rest are just not needed. Check which wires are used in your cable. In our case it turned out to be the orange and orange-white, green and green-white. Using a wire cutter, we need to cut and separate out the remaining four wires. We shall now be using these four wires for our workshop. Now simply cut the sleeve of the CAT5 cable carefully and dig out the unused wires, then cut them carefully. The other wires can continue to be connected to the RJ45 connector, and be used for the existing network.
Now that the wires are ready to be used for the workshop, twist the ends so that you have pointed tips. Refer to the circuit diagram above and connect all the elements—the switches, buzzers and RJ11 jacks. Finally, hook up the telephone’s cord to the RJ11 jack and power up the circuit with the battery. Now, your intercom device is all ready to be used.
Testing
Press any one switch to check if the buzzer beeps at both ends to confirm whether the ringer is functioning. Next, pick up the handsets at both ends, start a conversation with the person at the other end of the line to confirm the working of the intercom circuit. And Voila! the intercom is ready.
If the intercom doesn’t seem to be working properly, refer to the circuit diagram and find the fault to ensure that the connections of the circuit are correct. This short workshop described a method to install an intercom device in your home. To improve on this, you can design your own complicated array of switches in a more efficient manner by connecting more wires and handsets to make a larger intercom. July 18 SQL Server clusteringWhat is Clustering? These servers are referred to as "nodes". Each of the nodes talk to one another via a private network, sending a heartbeat signal between them. Should one node not communicate its heartbeat to the other node in the cluster the secondary node will take ownership of any dependent services being run by the node that lost communication. This process is referred to as "failover". A failover can occur both automatically (a server's heartbeat stops communicating) or manually. A manual failover is beneficial in the event that patching or some other form of maintenance is required at the physical server level. You would typically implement clustering in order to ensure that if you ever encounter hardware failure on the physical server hosting your SQL instance, your databases would continue to be available for dependent applications and their users. Unlike other clustering technologies that are implemented for better performance or for increased processing power via load-balancing, SQL clusters are designed for providing highly-available databases; eliminating downtime associated with hardware failure. This architectural concept is referred to as "High Availability Clustering" or "HA Clustering" for short. The service or groups of services that are hosted on a clustered node are respectively referred to as resources and resource groups. Since these resources must be available to all nodes in a cluster then they must reside on a shared disk array in the form of SAN-NAS disk. Each resource group will be mapped to a logical drive that is physically hosted on the shared disk array and will also have it's own associated IP address and network name. The SQL Server Installation Process on a Cluster If selected in the installation process, Notification Services and Analysis Services are also cluster-aware in SQL Server 2005. Conversely, the associated program files for the instance will be installed on the local drives of each of the clustered nodes in an identical fashion and registry values are set identically across all clustered nodes. Since the "Virtual" server resides solely on the SAN it can be "owned" by any of the nodes you allow. Each of the nodes can run these resources in identical fashion because each physical server/node has the program files and identical registry settings necessary to run the SQL instance. Furthermore, the users are oblivious to the underlying fluidity of the server. They connect to it as they would any other physical server: by server name (virtual server name in this case) if the default instance or by virtual server name\instance name if a named instance. This is key for application connectivity. Since the SQL instance simply changes ownership during a failover, connection strings the applications rely on to connect to their databases need not be recoded; the physical server may become unavailable, but the virtual server persists after the failover. Active/Active or Active/Passive Clustering Current Microsoft licensing policies require you to only license the active nodes running Microsoft SQL Server. The passive node need not be licensed. How Many Nodes? Pros and Cons Summary June 13 How to back up a database using script in SQL SERVER 2005 Use this script in order to backup a database : /* Author : Suprotim Agarwal Creation Date: Jan 2, 2008 */ CREATE PROCEDURE [dbo].[usersp_BackUpDB] @DBNAME nvarchar(50), @PATH nvarchar(200), @BCKUPNAME nvarchar(50) AS BACKUP DATABASE @DBNAME TO DISK = @PATH WITH NOFORMAT, NOINIT, NAME = @BCKUPNAME, STATS = 10 You can call this script using : DECLARE @return_value int EXEC @return_value = [dbo].[usersp_BackUpDB] @DBNAME = N'Northwind', @PATH = N'C:\temp\Northwind.bak', @BCKUPNAME = N'NW' SELECT 'Return Value' = @return_value GO Read more about this topic over here : How to see active connections for each Database in SQL Server 2005At times, we need to check the number of active connections for each Database on our server. This can be done easily using the following script. The script displays the DatabaseName, the number of connections and the login name : SELECT db_name(dbid) as DatabaseName, count(dbid) as NoOfConnections, June 12 How to send an email using SQL Server 2005 Sql Server Reporting Services provides a few global collections that
you can use in your reports to retrieve report information. One such
collection is Globals Globals contains global variables which can display information such as the report name, execution time or page number. You can use these variables as expressions in a textbox and place these textboxes in the report footer. Some of the expressions are as follows: Execution Time : = "Your report executed at " & Globals.ExecutionTime Page Number : ="You are viewing page " & Globals.PageNumber & " of " & Globals.TotalPages Report Path and Name : =Globals.ReportFolder & Globals.ReportName Similary you can also explore Globals.ExecutionTime which displays the execution date and time as well as Globals.ReportServerUrl which displays the URL of the SSRS server on which the report is being executed. Populate a table from a .CSV or .TXT file using SQL Server 2005You can use Bulk Insert or SSIS to import text/csv files. There are
some advantages and disadvantages using any of these methods. In this
article, we will explore how to use the OPENROWSET to read a data file
and populate a table. Note: In SQL Server 2005, OPENROWSET can read from a data file without loading the data into a target table. This lets you use OPENROWSET with a simple SELECT statement. Follow these steps: Step 1: Create a database called 'Employees'. Create a table called ' EmployeeDetails' in it using the script given below: USE [Employee] GO /****** Object: Table [dbo].[EmployeeDetails] Script Date: 04/11/2008 11:12:32 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[EmployeeDetails]( [EmployeeID] [nvarchar](50) NOT NULL, [EmployeeName] [varchar](50) NULL, [EmployeeAddress] [varchar](50) NULL ) ON [PRIMARY] GO SET ANSI_PADDING OFF Step 2: To run ad-hoc queries on the SQL server, you would first need to enable it using the following query: sp_configure 'show advanced options',1 RECONFIGURE WITH override GO sp_configure 'Ad Hoc Distributed Queries',1 RECONFIGURE WITH override GO Step 3: Create a txt/csv file with the following format on your C:\. The file is called 'Employee.csv' EmployeeID EmployeeName EmployeeAddress 1 Kat 23/Avenue. Park 2 Jim Jeoff Street 3 Tom Lifer Road Step 4: The final step is to run the query and populate the EmployeeDetails table USE Employee GO INSERT INTO EmployeeDetails(EmployeeID,EmployeeName,EmployeeAddress) SELECT * FROM OPENROWSET('MSDASQL', 'Driver={Microsoft Text Driver (*.txt; *.csv)}; DEFAULTDIR=C:\;Extensions=CSV;','SELECT * FROM Employee.csv') March 31 Fundamental Programming NamespacesThe .NET Framework class library provides access to system
functionality and is designed to be the foundation on which .NET
Framework applications, components, and controls are built. The
following sections describe many of the namespaces provided in the .NET
Framework class library. To browse the entire WinFX class library, see Class Library.( from microsoft.com) Fundamental Programming Namespaces
 Configuration Namespaces
Data and XML Namespaces
Globalization and Localization Namespaces
Interop Namespaces
Networking Namespaces
Reflection Namespaces
System.Reflection – contains classes and interfaces that provide a managed view of loaded types, methods, and fields, with the ability to dynamically create and invoke types. Security Namespaces
Serialization Namespaces
Service Namespaces
The namespaces in the .NET Framework for interacting with a variety of back-end server resources include the following:
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