Singtel replied my online enquiry:
I refer to your email of 17 September 2005 regarding internet
connectivity.
We had identified these possible situations that could have been
causing your connection problem. Please kindly carry out the following
checks to isolate the cause:
1) Hardware/modem issue
a) If you are using an USB modem and have too many devices (for
example printer, web cam etc) connected to the PC via the USB
ports, try removing some of them to see if the situation
improves.
b) The modem driver could be corrupted. To rectify this problem,
refer to the modem installation guide to un-install and re-
install the driver. When in doubt or in need of assistance,
do contact the modem vendor’s technical support for help.
c) If you suspect that the modem is faulty, contact the modem
vendor and engage their expertise in checking the modem.
2) Telephone line condition
a) Check to ensure that the cable is plugged into the correct socket.
b) Ensure the cable is plugged in securely.
c) Check that the telephone/fax machine sharing the ADSL line must
have microfilters attached to each of them.
If a microfilter is already in place, and disconnection still occur,
it is possible that the microfilter is faulty or incorrectly fixed. To
verify that a microfilter is correctly fixed, please refer to the
following website:
http://www.singnet.com.sg/technical/broadband/connect/index.htm
If the microfilter is fixed correctly, and connection problem still
persist, please try a direct connection. Direct connection means that
all devices using the telephone socket sharing the ADSL line are to be
removed. Only the cable from the modem is plugged into the main
socket.
3) Wall socket issue/telephone cable (RJ11) problem
a) If disconnection happens even via a direct connection, change the
telephone cable (RJ11) that connects the modem to the telephone
wall socket and monitor the connection.
b) If disconnection still happens, try to connect via another
telephone wall socket.
If the connection problem persists even after carrying out the above
actions, please kindly contact the technical help desk at 1800 8486933
(8am to 12midnight daily) for online test and troubleshooting. We
would need you beside your PC in order to assist our online test and
troubleshooting. If suspected to be line issue, arrangement will be
made for SingTel Line Department to contact you for internal line check
at your premises. The line check is chargeable at $20.00.
4) Sometimes, personal computers (PCs) infected with spyware/virus may
cause connection problems. May I suggest that you do the following to
check for any possible spyware/virus in your PC:
a) Run an online virus scan via the following website:
http://housecall.antivirus.com
http://security.symantec.com/sscv6/default.asp?langid=ie&venid=sym
b) Download anti spyware utilities to check for and remove any
spyware via the following websites:
http://www.singnet.com.sg/tou/misc/spyware.asp