diff --git a/app-common/src/main/java/im/angry/openeuicc/core/usb/UsbApduInterface.kt b/app-common/src/main/java/im/angry/openeuicc/core/usb/UsbApduInterface.kt
index 66c46c0..139dc84 100644
--- a/app-common/src/main/java/im/angry/openeuicc/core/usb/UsbApduInterface.kt
+++ b/app-common/src/main/java/im/angry/openeuicc/core/usb/UsbApduInterface.kt
@@ -47,6 +47,7 @@ class UsbApduInterface(
         }
 
         // Send Terminal Capabilities
+        // Specs: ETSI TS 102 221 v15.0.0 - 11.1.19 TERMINAL CAPABILITY
         transmitApduByChannel(
             tx = buildCmd(
                 0x80.toByte(), 0xaa.toByte(), 0x00, 0x00,