1) Open the 'Dial-Up Networking' folder in 'My Computer'.
2) Edit the DUN you wish to 'optimize' by selecting it and choosing 'Properties' as shown
3) Select 'Server Types' tab and setup the 'Advanced options' and 'Allowed network protocols' as shown below. Do not tick any other boxes, setup exactly as shown below.
4) Select 'Configure' from the 'General' tab.
5) Select 'Maximum speed' list and select either '57600' or '115200' or if possible '230400'. The 230400 setting can cause problems so should you have any set it to 115200 or 57600.
6) Select 'Connection' tab and make sure it is setup as shown - Data bits 8, Parity None and Stop bits 1. Then select 'Port Settings'.
7) Make sure that 'Use FIFO buffers' is ticked and then move 'Receive Buffer' and 'Transmit Buffer' to High. If you experience problems when connecting or online select the 'Defaults' option.
8) Exit 'Port Settings' dialog by clicking OK, now click on 'Advanced'.
9) Untick 'Use error control' and 'Compress Data', make sure that 'Use flow control' is ticked and 'Hardware RTS/CTS' is enabled.Make sure that 'Use FIFO buffers' is ticked and then move 'Receive Buffer' and 'Transmit Buffer' to High. Leave the Extra settings string box empty at this stage, select okay. Select 'Okay' and exit DUN setup. IMPORTANT: If you experience problems when online try ticking the 'Use error control' option to enable error control again or visit the Modem strings to see if a connection speed limit cap helps.
10) Dial the ISP using the optimized DUN you have just created. Check that in 'Status/Details' either 'Microsoft compression' or 'Stac compression' is shown under the 'Protocols' entry. If it is not then check that the ISP Supports Compression. NOTE: If your ISP supports Stac and you are not getting 'Microsoft compression' / 'Stac compression' or cannot ping servers then try enabling 'Error Control' in Step 9. If you still cannot negotiate 'Microsoft compression' / 'Stac compression' then enable 'Compress Data' in Step 9.