Medical Device

Radiocommunications Service

(MICS) Starter System

(December, 2020)

Starter System Overview

• A basic Medical Implant Communications System (MICS) demonstration

platform has been developed

• Operates using the world wide 402–405 MHz MICS band

• Provides a starting point for medical implant device developers

• Basic command / response display

• Nine basic Base Station (BS) commands

• Seven basic over-the-air Implant commands

• Base Station

• Connected to Host via USB -> Serial HW

• Processes and Responds to BS commands

• Forwards Commands Targeted to Implant via MICS

• Implant

• Processes and Responds to commands via MICS radio link

• Provides template for command extensibility

System Synopsis

• The Host GUI is coded in C# and represents a simple interface with basic

features and providing CRC protected command packets

• A command – response logger provides a running history of activity

• The Base Station uses a state-driven synchronous operating system and

relies upon a general command and response regimen (one command at a

time), with RF protocol handled by a ZL70123 module

• The implant uses a timer-based sequential time slot operating system for

command and response as well as its background processing, with RF

protocol handled by a ZL70321 (or ZL70323) module

Receive Response has the Target and Response (“B”, ”I”) devices swapped.

ID field used for encrypted security algorithm.

• Command Transmit without data payload ends with two CRC byte

Command Header with Payload Data

• Transmit Payload with N > 0 data bytes plus two CRC bytes

• Receive Response Payload with ACK/NAK byte and N data bytes + CRC

Command Example

• CCA Command (Clear Channel Assessment)

• cmdpkt = 0x42, 0x30, 0x31, 0x30, 0x31, 0x32, 0x30, 0x41, 0x42, 0x48

• outpkt = cmdpacket + two byte CRC (0x67 0x7E) at end of the transmit packet

• Send command array outpacket over serial link to Base Station

• Host GUI display shows CMD:B010120ABHg~ (Note: g~ is the CRC expressed in ascii)

• Response from Base Station is H010870xyBK, plus ascii formatted result:

7:1481

8:1501

Min Ch=3?? (Note: ?? is the CRC, and represents non-ascii printable characters in all cases)

CCA Command and Response

• Host GUI showing Clear

Channel Assessment

command and its response

from the Base Station

Start Link Command and Response

• Search and Start Link

linking

• MSG: “Linked with ID

000051” indicates a

successful link to implant