diff --git a/src/rfcomm.h b/src/rfcomm.h
index 193f208d8..f2909f757 100644
--- a/src/rfcomm.h
+++ b/src/rfcomm.h
@@ -257,43 +257,43 @@ void rfcomm_close_connection(void *connection);
 
 /** Embedded API **/
 
-// Set up RFCOMM
+// Set up RFCOMM.
 void rfcomm_init(void);
 
-// register packet handler
+// Register packet handler.
 void rfcomm_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type,
                                                     uint16_t channel, uint8_t *packet, uint16_t size));
 
-// Creates RFCOMM channel to a given server channel on a remote device with baseband address. A new baseband connection will be initiated if necessary.
-// This channel will automatically provides enough credits to the remote side
+// Creates RFCOMM connection (channel) to a given server channel on a remote device with baseband address. A new baseband connection will be initiated if necessary.
+// This channel will automatically provide enough credits to the remote side
 void rfcomm_create_channel_internal(void * connection, bd_addr_t *addr, uint8_t channel);
 
-// Creates RFCOMM channel to a given server channel on a remote device with baseband address. new baseband connection will be initiated if necessary.
-// This channel will use explicit credit management. During channel establishment, an initial amount of credits are provided.
+// Creates RFCOMM connection (channel) to a given server channel on a remote device with baseband address. new baseband connection will be initiated if necessary.
+// This channel will use explicit credit management. During channel establishment, an initial amount of credits is provided.
 void rfcomm_create_channel_with_initial_credits_internal(void * connection, bd_addr_t *addr, uint8_t server_channel, uint8_t initial_credits);
 
 // Disconencts RFCOMM channel with given identifier. 
 void rfcomm_disconnect_internal(uint16_t rfcomm_cid);
 
 // Registers RFCOMM service for a server channel and a maximum frame size, and assigns a packet handler. On embedded systems, use NULL for connection parameter.
-// This channel will automatically provides enough credits to the remote side
+// This channel provides automatically enough credits to the remote side.
 void rfcomm_register_service_internal(void * connection, uint8_t channel, uint16_t max_frame_size);
 
 // Registers RFCOMM service for a server channel and a maximum frame size, and assigns a packet handler. On embedded systems, use NULL for connection parameter.
-// This channel will use explicit credit management. During channel establishment, an initial amount of credits are provided.
+// This channel will use explicit credit management. During channel establishment, an initial amount of credits is provided.
 void rfcomm_register_service_with_initial_credits_internal(void * connection, uint8_t channel, uint16_t max_frame_size, uint8_t initial_credits);
 
-// Unregister RFCOMM service
+// Unregister RFCOMM service.
 void rfcomm_unregister_service_internal(uint8_t service_channel);
 
 // Accepts/Deny incoming RFCOMM connection.
 void rfcomm_accept_connection_internal(uint16_t rfcomm_cid);
 void rfcomm_decline_connection_internal(uint16_t rfcomm_cid);
 
-// Grant more incoming credits to the remote side for the given channel ID
+// Grant more incoming credits to the remote side for the given RFCOMM channel identifier.
 void rfcomm_grant_credits(uint16_t rfcomm_cid, uint8_t credits);
 
-// Sends RFCOMM data packet to the channel with given identifier.
+// Sends RFCOMM data packet to the RFCOMM channel with given identifier.
 int  rfcomm_send_internal(uint16_t rfcomm_cid, uint8_t *data, uint16_t len);
 
 #if defined __cplusplus
diff --git a/src/sdp.h b/src/sdp.h
index daac77387..1b500caa6 100644
--- a/src/sdp.h
+++ b/src/sdp.h
@@ -75,10 +75,8 @@ int sdp_handle_service_attribute_request(uint8_t * packet, uint16_t remote_mtu);
 int sdp_handle_service_search_attribute_request(uint8_t * packet, uint16_t remote_mtu);
 
 #ifndef EMBEDDED
-// register service record internally - this special version doesn't copy the record, it cannot be freeed
-// pre: AttributeIDs are in ascending order
-// pre: ServiceRecordHandle is first attribute and valid
-// pre: record
+// Register service record internally - this version creates a copy of the record
+// precondition: AttributeIDs are in ascending order => ServiceRecordHandle is first attribute if present
 // @returns ServiceRecordHandle or 0 if registration failed
 uint32_t sdp_register_service_internal(void *connection, uint8_t * service_record);
 #endif
@@ -88,15 +86,18 @@ void sdp_unregister_services_for_connection(void *connection);
 
 /** Embedded API **/
 
+// Set up SDP.
 void sdp_init(void);
 
 #ifdef EMBEDDED
-// register service record internally - the normal version creates a copy of the record
-// pre: AttributeIDs are in ascending order => ServiceRecordHandle is first attribute if present
-// @returns ServiceRecordHandle or 0 if registration failed
+// Register service record internally - this version doesn't copy the record therefore it must be forever accessible.
+// Preconditions:
+//     - AttributeIDs are in ascending order;
+//     - ServiceRecordHandle is first attribute and valid.
+// @returns ServiceRecordHandle or 0 if registration failed.
 uint32_t sdp_register_service_internal(void *connection, service_record_item_t * record_item);
 #endif
 
-// unregister service record internally
+// Unregister service record internally.
 void sdp_unregister_service_internal(void *connection, uint32_t service_record_handle);