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article-20h-interview.mw - tgtimes - The Gopher Times |
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git clone git://bitreich.org/tgtimes git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/tgtimes (git://bitreich.org) |
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README |
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article-20h-interview.mw (7107B) |
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1 .SH 20h |
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2 Breaking free from medical devices |
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3 .2C 122v |
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4 . |
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5 .PP |
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6 Unlike most USB gadgets around, medical devices require a specification |
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7 to be proven fit for handling patients data. |
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8 This makes doctor-hacking difficult for the sake of better control |
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9 over what is allowed for medical use. |
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10 . |
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11 .PP |
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12 While this may sound as a non-starter for many, not all doctors are |
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13 discouraged. |
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14 Interview with 20h: |
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15 . |
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16 .QP |
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17 You are __20h__, a doctor in Falken, the best village to live in |
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18 in Germany, is that correct? |
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19 . |
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20 .PP |
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21 Yes. |
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22 . |
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23 .QP |
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24 You managed to do some hacking around a medical device. |
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25 What was it? |
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26 How did it help you in your diagnostics? |
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27 . |
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28 .PP |
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29 I wrote \fCrfcommd\fR to have my spirometer print out the results |
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30 to a standard printer. |
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31 It helps me having a more detailed view on the results. |
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32 . |
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33 .PP |
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34 The normal printout is just like 8 centimeters wide. |
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35 Now it is A4. |
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36 . |
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37 .PP |
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38 I plan on using rfcommd to read out ECG data from a ECG for further |
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39 analysis. |
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40 . |
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41 .PP |
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42 The collecting computer is a gentoo hardened on x86_64, with a |
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43 standard bluetooth dongle, sending the print jobs via TCP/IP to a |
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44 network printer. |
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45 . |
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46 .PP |
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47 For printing there is a cups installation, converting the PCL output |
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48 of the spirometer to postscript for the network printer. |
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49 . |
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50 .QP |
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51 What software were provided to collect the data on a computer? |
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52 On which kind of system was that running? |
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53 . |
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54 .PP |
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55 Before rfcommd there was no collection of the data. |
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56 The spirometer has some built-in printer, |
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57 which is very expensive and the printout is small. |
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58 . |
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59 .QP |
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60 Are you using it often? |
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61 . |
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62 .PP |
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63 I/We are using it every day for printing out spirometry (lung |
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64 function) results. |
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65 . |
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66 .PP |
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67 By the way. |
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68 A secondary function why rfcommd has filters: We have |
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69 a sterilization device, which has a serial printout of sterilization |
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70 runs. |
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71 . |
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72 .PP |
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73 This is what rfcommd does print out too. |
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74 . |
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75 .PP |
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76 The features of rfcommd moved from: Accept every rfcomm request to |
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77 having filters per device mac, was because of those two devices. |
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78 . |
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79 .PP |
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80 But it will allow to have the ecg readout as a filter for free. |
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81 . |
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82 .QP |
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83 It had limited interaction, and yet you managed to made it available |
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84 from a linux computer. |
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85 How did you do it? |
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86 . |
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87 .PP |
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88 First I had a python script using pybluez to offer some bluetooth |
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89 printer service, which bluetooth clients connect to and send print |
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90 jobs. |
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91 . |
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92 .PP |
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93 But I migrated this to some C implementation and generalized it as |
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94 rfcommd so it is more modular for me and others can reuse it too. |
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95 . |
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96 .PP |
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97 Bluez stack had some rfcomm client application, but it was removed |
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98 in newer version because they hate commandline users. |
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99 . |
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100 .QP |
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101 Was it difficult? How long did it take? |
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102 . |
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103 .PP |
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104 Digging around bluetooth is difficult. |
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105 It looks similar to TCP/IP, but is its own terminology, protocols |
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106 and principles. |
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107 Look at rfcommd for how to announce some service. |
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108 . |
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109 .PP |
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110 It took me two weekends to write rfcommd as it is now. |
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111 . |
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112 .QP |
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113 What would you advise to designers of such devices to make everyone's |
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114 life easier? |
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115 . |
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116 .PP |
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117 If you mean medical devices: Please open source all firmware and |
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118 open up all schematics. |
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119 In ten years you will be dead or in pension but still people can |
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120 extend or update your devices. |
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121 . |
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122 .PP |
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123 And second: Never have specific assumptions and fool end users into |
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124 costly standard. |
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125 You never know better than your users. |
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126 . |
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127 .PP |
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128 For example in the spirometry description, they say, that only some |
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129 bluetooth printers are compatible. |
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130 . |
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131 .PP |
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132 This is due to the bluetooth standard not having defined, \fBwhat\fR |
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133 is sent to bluetooth printers. |
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134 . |
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135 .PP |
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136 It should be the minimum, to define this, as it is in the USB |
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137 printing standard. |
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138 . |
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139 .QP |
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140 What kind of protocol interface would have been the easiest? |
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141 . |
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142 .PP |
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143 The easiest protocol interface, also considering security and data |
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144 protection standard, would be ssh over TCP/IP. |
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145 Everyone knows SSH, it can be integrated into everything and it is |
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146 easily upgradable to newer security standards. |
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147 . |
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148 .QP |
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149 What does it permits to do that was not possible before? |
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150 . |
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151 .PP |
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152 With the spirometry data ready as simple text data, I can further |
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153 process it using standard unix tools, in case I ever need this. |
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154 . |
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155 .QP |
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156 Are other people using it in the practice as well? Even indirectly? |
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157 . |
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158 .PP |
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159 My nurses use it mainly. |
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160 They press the »print« button on the spirometry device and it prints |
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161 the results. |
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162 . |
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163 .PP |
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164 I, as doctor, only see the printed out results and explain them to |
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165 patients. |
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166 . |
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167 .QP |
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168 Does she have to use command line interface for that? |
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169 . |
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170 .PP |
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171 No, it's all practical. |
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172 The spirometer starts its bluetooth client for rfcommd and rfcommd |
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173 runs the spirofilter printing filter script, which invokes lpr(1). |
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174 . |
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175 .QP |
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176 Are there many situations like that, where cumbersome interfaces |
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177 makes life harder for working with medical devices? |
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178 . |
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179 .PP |
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180 Yes, it's built into all medical devices to enforce proprietary and |
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181 expensive Windows software to be bought. |
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182 . |
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183 .PP |
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184 For example the newer version of my ECG device has some undocumented |
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185 network mode. |
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186 The ECG standard I will be using over serial was defined in 1990. |
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187 Since then old devices only got bluetooth and ethernet, but did |
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188 nothing else new. |
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189 . |
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190 .PP |
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191 The price stayed the same, of course. |
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192 . |
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193 .QP |
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194 Do you think designers would benefits themself from offering another |
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195 interface that is easier to use? |
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196 . |
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197 .PP |
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198 In the short term viewpoint it protects you from competitors to |
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199 enter the market. |
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200 But in the long run, this now stops me from easily processing patient |
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201 data for further research. |
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202 I am using a 25 yr old ECG and some 10 yr old spirometer. |
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203 . |
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204 .QP |
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205 Are there any similarities in other devices to reuse the existing |
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206 work you just did? |
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207 . |
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208 .PP |
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209 Yes. |
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210 Bluetooth is the new hype in medical devices. |
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211 All those smart devices for body measurement are for example BLE, |
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212 some insecure bluetooth standard to read out key=value from bluetooth |
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213 clients. |
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214 Some bled(8) should be easy to write. |
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215 . |
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216 .PP |
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217 Nearly every medical device still has some serial port, either for |
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218 communication or measurement. |
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219 . |
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220 .PP |
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221 For measurement this will never die out, since raw data is required. |
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222 . |
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223 .PP |
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224 And some serial2bluetooth, that's what I am using for my practical |
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225 examples. |
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226 . |
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227 .QP |
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228 Would it have been possible to build such device yourself from |
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229 parts, but with sane interfaces instead? |
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230 . |
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231 .PP |
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232 Building such a device is not the hard part. |
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233 The hard part is licensing the device as being a medical device. |
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234 . |
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235 .PP |
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236 I am, as a doctor, am allowed to license some medical device for |
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237 my patients. |
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238 But if I'd want to sell or give this device to some other doctor, |
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239 I'd need some EU medical device license. |
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240 . |
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241 .PP |
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242 This is a complex process. |
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243 . |
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244 .PP |
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245 You have severial medical device classes. |
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246 Some always require some EU-wide licensing. |
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247 . |
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248 .PP |
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249 The logic of some ECG is very simple. |
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250 But licensing it for selling is what makes it expensive and/or keeps |
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251 the competition low. |
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252 . |
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253 .QP |
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254 What do you advise to people also stuck with cumbersome device, but |
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255 without reverse engineer superpowers? |
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256 . |
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257 .PP |
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258 Force the device producers to open up standards. |
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259 Write into contracts, that devices have to be interoperable, so |
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260 producers need to adapt. |
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261 . |
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262 .PP |
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263 It's the same for software. |
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264 If you can't write it on your own, force them to open up standards, |
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265 because you want to extend the software. |
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266 . |
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267 .PP |
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268 For extension of software, reverse engineering is legal. |
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