Sunday, October 2, 2011

Bank Negara instructed credit card issuers to use payment received to settle highest interest rate item first. But...

Bank Negara has issued new guidelines to be implemented from 1 October 2011, requiring all credit card issuers to use payment received to settle highest interest rate item first.

Generally, Malaysian credit cards interest rates per annum of retail transaction range between 13.5% to 17.5%. Cash advanced rate can be as high as 18% per annum. Balance transfer rate ranges from 0% to 18% per annum. Interest rate of instalment payment plan also ranges from 0% to 18% per annum.

Let's say in a particular month, your credit card balance is as follow:

Retail transactions with interest @ 16% p.a. = 2000
Balance transfer instalment @ 0% p.a. = 500

If you pay 1000 for that month:

  • In the worst case scenario, 500 of your payment is used to offset the balance transfer instalment, and only the remaining 500 be used to offset the retail transactions with 16% p.a. interest.
  • In the best case scenario, 1000 of your payment is used to offset the retail expenses, and none will be used for balance transfer instalment.
However, the best case scenario for this month might not be good to the card holder, if the bank consider the balance transfer instalment be defaulted and charge a hefty 18% p.a. interest rate thereafter. The only way for the card holder to maintain the 0% balance transfer rate is to pay the monthly credit card charges in full until the balance transfer instalment is settled.

I believe Bank Negara should have think of this kind of scenario, and the guidelines should be comprehensive to ensure card holders are charged with the lowest possible interest charges for current and also subsequent months. Otherwise, scenario like the above might form a trap, causing the card holders end up need to pay even more interest.

Thursday, September 29, 2011

Wireless antenna technology: SISO, SIMO, MISO and MIMO

The wireless data transmission system consists of 2 parties: the transmitter and the receiver, whereby data is transmitted into the air from the antenna of the transmitter and received by the antenna of the receiver.

In a Single Input Single Output (SISO) system, both the transmitter and the receiver have one antenna, and data transmission over the air is through a single radio frequency (RF) signal chain.


An example of SISO type of wireless is Bluetooth.

Multiple antenna technique has been developed to improve wireless performance.

In a Single Input Multiple Output (SIMO) system, there is one antenna at the transmitter side and multiple antennas (each with an RF chain respectively) at the receiver side.



In a switched diversity or selection diversity implementation, the receiver chooses the best antenna to receive a stronger signal from the transmitter. In a maximal ratio combining (MRC) implementation, the receiver combines signals from all its antennas so that to maximize the Signal to Noise Ratio (SNR).

The Multiple Input Single Output (MISO) system is the other way round, with multiple antennas (each with an RF chain respectively) at the transmitter and a single antenna at the receiver.


A technique known as Alamouti Space Time Coding (STC) is employed at the transmitter with 2 antennas, allowing the transmitter to transmit signals both in time and space. This means data is transmitted by the 2 antennas at 2 different times consecutively.

Multiple Input Multiple Output (MIMO) system is commonly used in today's wireless technology, including 802.11n WiFi, WiMAX, LTE, etc. Multiple antennas (and therefore multiple RF chains) are put at both the transmitter and the receiver.


A MIMO system with same amount of antennas at both the transmitter and the receiver in a point-to-point (PTP) link is able to multiply the system throughput linearly with every additional antenna. For example, a 2x2 MIMO will double up the throughput.

Spatial Multiplexing (SM) technique is used in MIMO to enable signal  to be transmitted across different spatial domains. This is used  to provide additional data capacity.

Therefore, when buying a Wireless-N access point or router, to get a stabler WiFi with higher bandwidth, look for those that support MIMO and with more antennas.

Acknowledgement: the above diagrams are taken from the Radio-Electronics.com website.

Thursday, September 22, 2011

Using NetSetMan to change Windows network settings with a single mouse click

If you are using a laptop, you must have faced the problem of having to manually adjust the network settings to connect to the network (either LAN or WiFi) in different places. This is really a tedious thing, isn't it?

Although many places make use of DHCP to automate the IP address assignment (so that you are free from the hassle to manually set the IP address, subnet mask, gateway IP, etc.), you might probably still need to do some adjustment to some other settings, such as the SMTP email server, the DNS server, the default WiFi AP you want to connect with, the default printer, etc. Worse still, there are places that don't make use of DHCP server, and you have to manually change the network settings, especially the IP address, subnet mask and gateway IP, in order to connect and use the network there.

For example, the DHCP server might assign you with the ISP's DNS servers, and you prefer to use Google's DNS servers instead. In some other places, you cannot use Google's DNS servers because the firewall might have blocked DNS request to WAN, and you have to use their internal DNS server.

I found NetSetMan to be a very handy tool allowing you to quickly change your Windows network setting with just a mouse click to connect to the network in different places. It lets you pre-configure the network settings and save them in different profiles. By switching the profile, all the pre-configured settings will be switched over accordingly.


NetSetMan is free for personal non-commercial use. The free version lets you set up to 6 network profiles, while the Pro version lets you set unlimited profiles.

You can customize the settings in each profile for:
  • IP address (to use DHCP or manual setting)
  • DNS servers
  • DNS domain
  • WINS servers
  • Default WiFi AP
  • Default printer
  • Network adapter status (activate, deactivate or restart)
  • Your PC name
  • The workgroup / domain to join
  • SMTP server for email sending
  • Network drive mapping
  • Browser homepage and proxy setting
  • Local "host" file setting for mapping domain names with IP addresses. Normally the setting in this "host" file will supersede the DNS result
  • IPv6 settings
NetSetMan also allows you to run Windows script before and/or after a profile is changed.

It also has feature to allow you to copy-and-paste profile settings from one to another. This is handy to create a new profile where most of the settings are the same with the existing. You just need to make a copy, and modify those settings that need to adjust with.

Hint: Click on the "Older Posts" link to continue reading, or click here for a listing of all my past 3 months articles.