diff --git a/6-asyn-troubleshooting.md b/6-asyn-troubleshooting.md
index 582a321fd373945acda709908a996846d8ce0cc2..424ca8cc7c7366e3bc8bbe4a5b07f396e224edea 100644
--- a/6-asyn-troubleshooting.md
+++ b/6-asyn-troubleshooting.md
@@ -66,7 +66,7 @@ The **traceMask** determines which messages are printed on the IOC's console:
 * **traceError** should always be on
 * **traceIODriver** is useful for looking at serial/ethernet communication (when connected to the correct asyn port)
 
-The **traceIOMask** deterines how the messages are printed on the IOC's console:
+The **traceIOMask** determines how the messages are printed on the IOC's console:
 * **traceIOASCII** prints the messages as ASCII strings (this works well for messages that only include symbols that appear on a keyboard)
 * **traceIOEscape** prints the messages and unprintable characters using escape sequences (starting with a backslash)
 * **traceIOHex** prints the messages as a series of byte values in hexadecimal (without the **0x** prefix)