diff --git a/ads1298.c b/ads1298.c
index 1fce6e0..2187c93 100644
--- a/ads1298.c
+++ b/ads1298.c
@@ -112,8 +112,8 @@ void ads1298_initialize(ads1298_info_t *p_info) {
         NRF_LOG_FLUSH();
     #endif
     
-    // Prepare packet header to ID as "ADS1298"
-    p_info->usb_buffer[0] = TN_IC_ADS1298;
+    // 0xDF = see extended table
+    p_info->usb_buffer[0] = IC_ID_ADS1298;
 }
 
 void ads1298_uninitialize(void) {
diff --git a/main.c b/main.c
index 1c2c4f1..0b34d3c 100644
--- a/main.c
+++ b/main.c
@@ -74,7 +74,7 @@ APP_USBD_CDC_ACM_GLOBAL_DEF(m_app_cdc_acm,
                             APP_USBD_CDC_COMM_PROTOCOL_AT_V250);
 
 __STATIC_INLINE void reset_buffer_count(uint8_t *buffer_start) {
-    buffer_start[0] = 0;
+    buffer_start[1] = 0;
 }
 
 __STATIC_INLINE void increment_packet(uint8_t *buffer_start) {
@@ -168,7 +168,7 @@ void read_ic_settings(uint8_t* new_packet) {
             // read all registers into m_info.registers
             ads1298_readback_registers(&m_info); 
             // Send back over USB.
-            usb_send_push_ex(REGISTER_READBACK_PREFIX, REGISTER_READBACK_ADS1298, 
+            usb_send_push_ex(CTRL_REGISTER_READBACK, IC_ID_ADS1298, 
                                     m_info.registers, ADS1298_REGISTER_COUNT);
             ads1298_start_rdatac();
             ads1298_standby();
diff --git a/pca10056/blank/config/custom_board.h b/pca10056/blank/config/custom_board.h
index bef4717..3609269 100644
--- a/pca10056/blank/config/custom_board.h
+++ b/pca10056/blank/config/custom_board.h
@@ -46,14 +46,35 @@
   #define TN_MISC_RTT_REQUEST      0x1
   
   // #################### RESPONSE CODES ####################
-  
+  // #NOTE: 0x01 and 0x02 are reserved (for now) for legacy BLE reasons. I should deprecate and
+  // remove these.
+  #define CTRL_STAT_INFO_STRING         0x01
+  #define CTRL_STAT_INFO_BYTES_SENT     0x02
   #define CTRL_STAT_INFO_PERIPHERALS    0x03
   #define CTRL_STAT_INFO_HW_FW_VERSION  0x04
   #define CTRL_STAT_INFO_WHO_AM_I       0x05
   
-  #define REGISTER_READBACK_PREFIX      0xC8
-  #define ID_REGISTER_READBACK_PREFIX   0xC9
-  #define REGISTER_READBACK_ADS1298     TN_IC_ADS1298
+  #define CTRL_STAT_INFO_BATTERY_LEVEL  0xB1
+  // For register readback, the following bytes will be ic-dependent, as
+  // some devices have more than 62 bytes worth of registers, so it may
+  // need to be split up into pages. 
+  #define CTRL_REGISTER_READBACK        0xC8
+  
+  #define CTRL_ACK_RTT_REQUEST          0xE0
+  
+  // %%% IC Identifiers %%%
+  // I want a SINGLE table for 8-bit IDs corresponding to different ICs
+  // These values can be anything from 0x06:0xFF, as long as it doesn't conflict
+  // with any of the reserved ones from above. 
+  
+  // If the USB packet leads [0] with the ID, then it is a data packet 
+  // in the typical format of [ID, Serial, ...data] where the length of data
+  // should be statically determined in advance.
+  // For example, with the ADS1298, the packet length is determined based on the
+  // channel count (see: ads1298_set_data_buffer_length for more details)
+  // #define RESPONSE_PACKET          0x00
+  #define IC_ID_ADS1298            0xD1
+  #define IC_ID_EXT                0xFF // see next byte for extended table
   
   #define FIRST_NIBBLE(x)  ((x >> 4) & 0xF)
   #define SECOND_NIBBLE(x) (x & 0xF)