If countries fix their exchange rate, the exchange rate channel of monetary policy does not exist. Is

Question:

"If countries fix their the channel of monetary policy does not exist." Is this statement true, false, or uncertain? Explain your answer.
Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...