Consult your tech support for assistance on how to do this. In an extreme case, it may be necessary to upgrade the communications port. Unsuitable UART chip for your COM port. If you believe your computer may be in this situation, have it checked by a professional and have the chip replaced with a 16550 UART chip, or an additional COM port with this chip installed. Faulty or incompatible modem.
Some modems are just poor quality and never work very well in certain conditions.
Other modems may not be fully compatible with those at Alphalink, over certain line conditions. The best way to check this is by substituting your modem with another modem or modem brand if you have already exhausted modem initialisation string suggestions in your modem manufacturers handbook. Trading as Alphalink Reg.