waKas malik
you have designed a successful product provided you have done your homework in the designing phase.
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The other day I was changing some data types in our schema script and thought of sharing it as it might becomes trickier for some us. I use...
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One of the basic step before coding is creating the flowchart. A flowchart is a type of diagram, that represents an algorithm or process, sh...
Sunday, December 22, 2019
Monday, February 20, 2017
Introduction to Voice Over Internet Protocol (VOIP)
What is VOIP:
VOIP stands for
Voice Over Internet Protocol. It’s a great new way from to use the power of
internet to make and receive phone calls. If you have a high speed internet
connection then you can use VOIP and begin making phone calls using your
regular touch tone phone. Just like sending an e-mail through the internet VOIP
service provider does the same thing with voice and the best part is that you
will be able to call anywhere at anytime and save money too. VOIP is also
called broadband phone as it uses high speed internet connection which is also
called broadband connection.
History:
The concept of VOIP
comes from the concept of text chatting. In earlier days when internet was
invented there was big problem for the general users that how they can get
access to it because to get an access to internet there is need for a physical
connection between the user and the internet. It is not possible to cover
million and billions of users around the world through means of physical
connection. But there exists a physical connection around the world that is
already in use by billions of people to connect anywhere in is world with their
friends and relatives and that physical connection is our local phone cable. By
using this cable they can overcome the physical connection problem but then
another comes up and that is local phone signals are analog and the computer
sends and receive digital signals from the internet. They over come this
problem by inventing modem whose function is to convert digital signals into
analog and analog signals into digital. So users are connected to internet and
using it for different purposes including chatting. Most of the users around
the world were using internet because of chatting. They progress further in
increasing the speed of internet and then were able to transfer voice over
internet which was popular all around the world as voice chatting and is still
in use as VOIP service is not that much cheaper for every user. From voice
chatting they get this concept of making and receiving phone calls by means of
internet as they are already using the resources of the telephone. Now a day we
are still connecting to the internet by means of telephone cable but there is
tremendous improvement in its speed and its facilities. VOIP is one of the most
important facilities of the internet.
Requirements for VOIP:
In order to get a
VOIP connection following are the requirements:
- Broadband Internet connection (DSL or Cable).
- A regular touch tone telephone.
- A VOIP phone adapter.
- A VOIP service provider account.
How VOIP works:
You
connect your telephone to your high-speed Internet connection using the VOIP
phone adapter. Pick up the phone, and use it just like you do today. When you pick up the phone, the VOIP phone adapter
converts your voice into data and sends it through the Internet like an email. The
VOIP service provider’s network sends the call where you want it and translates
it back into voice. When the person you're calling picks up the phone, it
sounds just the same as any other call. When someone calls you, they dial your
number, your phone rings, and all you have to do is pick up and answer it. Once
you connected a VOIP adapter with your cable or DSL modem then your phone calls
are routing through the internet. Below is a diagram that how its works and
general procedure:
VOIP Setup |
- VOIP adapter sends your phone call across the Internet.
- Your calls go through your modem.
- Your VOIP phone adaptor splits your high-speed broadband Internet connection.
- Your Internet connection should work as it did before you installed the VOIP phone adaptor sending emails and other web data to your personal computer.
- Your phone calls are sent through your VOIP phone adaptor to your regular or cordless phone.
·
First and one of the important advantages is
that it will lower your phone bills and especially if you have an international
connection or you are using calling cards.
·
Secondly wherever you live in this world you
can get a local telephone number of your choice of country regardless of the
geographical difference of both the countries. Let’s take an example if you
live here in USA
but still you can own a UK
number. In this way you and your UK friends save a lot of money on
phone calls as both you have the same area code that’s possible now with the
power of internet and VOIP service.
·
You can get all great features like Caller ID
with Name, Call Waiting Voicemail and Conference Calling included at no
additional cost.
·
There are number of additional features that you
can get like: 911 Dialing Call transfer, In-Network calls, area code selection,
Click 2 Call, Call Return, Caller ID block, International Call Block and Ring
List.
·
Soft
Phone: Whether you're traveling across the globe or just into the next
room, carrying on a conversation doesn't have to mean carrying extra equipment.
Download Soft Phone software and you can turn any PC or laptop into a
full-functioning telephone. Soft Phone is a screen-based interface that works
just like your telephone keypad. You can make a call, receive a call, and pick
up your voicemails too.
- One major disadvantage of VOIP is the quality of the sound which can be uneven, and phone calls often have lot of delay with lot of echo. It makes conversation difficult .To get lower bandwidth, the voice compression algorithms and echo cancellation requires additional processing power that makes digital phones more expensive than analog phones.
- If your cable, DSL or electric power goes out so does your phone line.
- No emergency reliability. Maybe you will never need it but if you have to use 911 you have to give exact address and name, they have a hard time tracking where you are and this could cost you valuable seconds.
Thursday, February 16, 2017
Calculate Time Difference Between Two Clocks in String Format
The other day I was looking for calculating the time difference between two clocks in String format. I could find a better solution, so I wrote a custom one. Take a look at the Java Code below:
The above code should work as long as you keep in mind the pre and post conditions.
Pre-Condition:
This function assumes that all four parameters are present so if even one of them is missing it will return zero.
Post-Condition:
This function will also make sure that the ending time cannot be before the starting time if it is it will return the error message.
1: public static String calTimeDifference(String startHour,
String startMin, String endHour, String endMin){
2:
3: String total = "0";
4:
5: if (!StringUtils.isEmpty(startHour) &&
!StringUtils.isEmpty(startMin) &&
!StringUtils.isEmpty(endHour) &&
!StringUtils.isEmpty(endMin){
6:
7: int stHr = Integer.parseInt(startHour) * 60 ;
8:
9: int stMn = Integer.parseInt(startMin);
10:
11: int enHr = Integer.parseInt(endHour) * 60 ;
12:
13: int enMn = Integer.parseInt(endMin);
14:
15: int startTime = stHr + stMn;
16:
17: int endTime = enHr + enMn;
18:
19: if (endTime > startTime){
20:
21: int durationHr = (endTime - startTime)/60;
22:
23: int durationMn = (endTime - startTime)%60;
24:
25: total = Integer.toString(durationHr) + " Hr and "
+ Integer.toString(durationMn) + " Min" ;
26:
27: }
28:
29: else{
30:
31: total = "Ending Time cannot be before Starting Time";
32:
33: }
34:
35: }
36:
37: return total;
38:
39: }
The above code should work as long as you keep in mind the pre and post conditions.
Pre-Condition:
This function assumes that all four parameters are present so if even one of them is missing it will return zero.
Post-Condition:
This function will also make sure that the ending time cannot be before the starting time if it is it will return the error message.
Thursday, March 3, 2016
Disabling Default Spring File Extension Response Mapper
The other day I was trying to implement a file download functionality, which takes the filename as a path variable and returns you the uploaded file metadata. In my case file extension was not matching the response type and Spring was throwing this exception below:
org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
The problem was that Spring treats the part after the dot in the url as a file extension and was trying to determine the matching response type and didn't find any matching converter, which result in throwing the above exception.
To solve we can simply disabled the default suffix-based content negotiation and can use the produce annotation to tell Spring what response type should be used.
Code:
1: @Configuration
2: public class ContentNegotiationConfig extends WebMvcConfigurerAdapter {
3: @Override
4: public void configureContentNegotiation(final ContentNegotiationConfigurer configurer) {
5: // Turn off suffix-based content negotiation
6: configurer.favorPathExtension(false);
7: }
8: }
Note: It is important to use the configuration annotation so this property can be set before starting the spring container.
Labels:
configuration,
entry point,
request,
response,
spring,
spring boot,
spring security,
web development
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