PENTEST VIA CELLULAR NETWORK (II): HOLOGRAM NOVA GLOBAL 2G/3G MODEM
- Layout for this exercise (Smartphone and Raspberry Pi / SIM card / Modem):
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo7FqF2Oo97s68vJR24w7sfdnEWH47mdiYMb9lg_kRSGc1EAnw_H41GRb0So_ak4KRvVRsMYSAmbE1KbB47_UPFDhnQyRUWLv_U04EzhZnWqhvTUVNAkOaqZdReUQF3E16sBSm_U5jD05S/s400/screenshot.22.jpg)
1 - Hologram Nova Global 2G/3G Modem
- The modem Hologram Nova is a global 3G/2G cellular modem purpose-built for IoT and single board computers like the Raspberry Pi.
- Paired with Hologram's CLI/Python SDK and global cellular network, the Nova is a simple plug-and-play modem for instant connectivity and secure data messaging.
- At the moment of writing this text, it can be bought online at a price of $49.
https://hologram.io/store/nova-global-cellular-modem/36
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFXzCHGs_z5eszhW1gGA8TT4nGwehFMvSVOZNVB-EV_1mF2fuuPG3vQff6NdeFrDgfCmalZEyIdVjd0thIfoen6Qco605L9bXCne5BYBVVSQHDEDszF8qsngj0-QHIMQodGHERFM9x051u/s1600/screenshot.10.jpg)
- Before the Nova modem can be operational the SIM must be activated (as done at previous exercise) so that it can gain access to the cellular network.
- The SIM card is inserted into the slot of the bottom of the Nova board, being careful that the Nova is not plugged-in at that moment:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaBc9rAAkKzbqWTVrTEsUL9chv7WepZlxs2iNtE7scU94LjWYBDq_jG_AL5ik_v4L0t47At_3iYnpqZPPWxtNQV9LHAYftMoEQglPF7dANdUixF4i8Dm5_oyXe6xZRrCpakhvjsb1vMSLZ/s400/screenshot.24.jpg)
- The Nova modem kit includes two quad-band flexible UFL anntenas, operating over 850/900/1900/2100 MHz bands.
- The larger black anntena is expected to provide better reception, though the yellow antenna has the benefit of fitting better due to its smaller size.
- The anntenas are attached pressing firmly down the gold UFL connector:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe3kR3nZ86NAUSsT94YMuec0TB-6ofkBD-F00lB2N2_JvWMs1IUyoaBQBYW0XVFfunM2297kR6RDPHOUR1BbkpAN-fPUGKmXtXk0H-cdxGsqwZcXSzJec2UPqt5FqgL1TsMK51AlpHUEwC/s320/screenshot.25.jpg)
- Once the modem is operating correctly there are two LEDs (blue and red) providing feedback about what is going on inside the modem:
2 - Hologram Python SDK
- The SIM card is inserted into the slot of the bottom of the Nova board, being careful that the Nova is not plugged-in at that moment:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaBc9rAAkKzbqWTVrTEsUL9chv7WepZlxs2iNtE7scU94LjWYBDq_jG_AL5ik_v4L0t47At_3iYnpqZPPWxtNQV9LHAYftMoEQglPF7dANdUixF4i8Dm5_oyXe6xZRrCpakhvjsb1vMSLZ/s400/screenshot.24.jpg)
- The Nova modem kit includes two quad-band flexible UFL anntenas, operating over 850/900/1900/2100 MHz bands.
- The larger black anntena is expected to provide better reception, though the yellow antenna has the benefit of fitting better due to its smaller size.
- The anntenas are attached pressing firmly down the gold UFL connector:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe3kR3nZ86NAUSsT94YMuec0TB-6ofkBD-F00lB2N2_JvWMs1IUyoaBQBYW0XVFfunM2297kR6RDPHOUR1BbkpAN-fPUGKmXtXk0H-cdxGsqwZcXSzJec2UPqt5FqgL1TsMK51AlpHUEwC/s320/screenshot.25.jpg)
- Once the modem is operating correctly there are two LEDs (blue and red) providing feedback about what is going on inside the modem:
- The blue LED represents whether the modem is on/off.
- The red LED indicates the network status: off (no network detected), double blink(2G), rapid blink (3G), solid (connected)
2 - Hologram Python SDK
- The Python SDK and Hologram CLI are available on Github as open source.
- The Hologram Ptython SDK allows to connect and communicate the Hologram SIM card and the Nova USB modem with other IoT platforms for cellular connectivity:
https://github.com/hologram-io
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQLBJoMGXkG0-0hh4LevGX154tOJYUUS-8BhNVS8sBySwWWWGyBeSz7PekZnOs5xKazQ883yZidaIfbt9s8dkNd4UaX9_EpJ7TuFxojdRWs_5eWV_UFzFEpHjbTkd0hBDf82rg6F3N8yfn/s400/screenshot.1.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0ij27N6z2UEgl76NNH52emaylltlF6trABF1ewgWZrzMwzAKhkqOBC1UjsGsV-pqoeGkDuPPW8qW6IldUvDBfc18qT1tmcjlMmoyu2Hxgg7uOdVdgZqMV3pbYyIL0e0qSt8oK5FLc3F7r/s400/screenshot.2.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWpjaTIZzcsO4-v-LxKKIery6KZOyB-_MX58IrvMQckv_ltTRPn1zmBXNkn4lBDIchZu6OB3aBQcythvrMvUFOtrZWbCpWnpUh1hYnbEpKQYD9SCpWvW_ZE0JTyGkWnjL21_z_PkOFzAHz/s640/screenshot.3.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhu57Th0R0C2l4f3X4suqWFl1ExT-JqiRkCtZBmr5mkflS-0LZ8ZWk0e3Wph90cr4ry1IAwSxmvTlFJxDHVbRurE5P_e8Fsy_UCT-sE_F41ttZjzZJ69QQP-CT-pYK9-48JXBGjUFbXNZN6/s400/screenshot.43.jpg)
- Installing the Hologram Python SDK to the Raspberry Pi device:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL_Of2bb573W9AFH_G6M0rUfSzs_-FG3q9lHnr8Xk3MDxtZBh9EI8UPruNunQd3L9ubDcDHdxqpPz8zRTif313ooVHLEPG4M7ahu6xTo2OCGHm0h5TD_-bSNN08BKfOrHKZb-I0FBWUl1S/s1600/screenshot.4.jpg)
..............................
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-gEELk2rkKQGYEhXAcA2YkhPoBUrX-RrhGwcnIM3hSJCRJlJ-6lOh9V4QM05Izg2KYnl3rTx-AIUAIGV0tJfVZM-NUyTtCY6G9gY_qIWvXeXMyDGNZU0I1DQ72TmTs2VsbTo6rzaXOvXp/s1600/screenshot.5.jpg)
- On next exercises this Python SDK platform will be used abundantly:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip3Ro2OQAsSZrXprvzL8OOQvSpd1fnjKVFQCse0cNCZg8zBkrqJbUm6DHl_UtIoX-yp91t_6rxnZbukJJjp6HyeJDL5QkZn9N60bnRChDVtAkWPKeAJ1o2SG1sHdhV2qtBA9CrpAABYys8/s1600/screenshot.6.jpg)
3 - Checking the functionality of the modem
- First of all, let's check that Raspberry Pi detects the modem connected to one of its USB ports:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhs_3z5jGF96VnoPpiNs2mYf13ydrDJud1zW0LShBi-fWt4QSb-yBG-z7Ipq0d2_c22tU967f-Yomr75H7iYDCQJ_nsddwjbbiJZUcLt_R6RIvovdvFqXzojJaA2xKIIObSfdBR6_mpoSol/s1600/screenshot.1.jpg)
- Accessing available ports:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTOomvESxyeMjs-ekDmRIRVIvcdBWEnOWkK3FARF0xb6PxwrBYByIVLZ_vgc49SR3Bd_YqG3MqjKAuTbJZYdpM6xio-Uj1Kl-Zq0QG2ouaZzd3rWfo9jNgYBlukHbM_PR00Nwm1iXuwJQm/s1600/screenshot.2.jpg)
- hologram command has got several options:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3HJFMYkFiRzZHCx-E7-qQSopeCb0CJMIAUXDMdrfMJlUQYINj7qFnM5qG04yG-PNxNnRm7sLAb-6UqMX7hMC1fp88XSyHM_aGCPe8zZ-sjgZSRAggKdT0lk-fL3vRgvtUUb-O6PeHZ02r/s1600/screenshot.3.jpg)
- Detecting the type of modem:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT9ihtiLRDkl3M65xukD0-_zXeQ78ZLTGkH5ovJyIzQ5g0HqOno7ZJfQc6V6Vz5osNB97LIA0XU8UIsm0unXQhsBv_llR7ih9_MFduNm8N1bCUipuVypMoltBnd0ECsIUeJ6witidjb5u_/s1600/screenshot.4.jpg)
- Printing the celullar network available:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigh7ekl0Jcri8OM_TosagA6GCRnNM3bFtlt8PkGnUS9f-wNa-3L6V1fJckY3Rlp9uCIEPcJwy9iNBTN1DDlIeJ7JIdxbyww_d2skbDimMKv4nnPn86WFInsdUeKvO49LpHj7kuCIP9_DOz/s1600/screenshot.5.jpg)
- Printing the SIM card number used with the modem:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZh_HsY_bs5iuFOW4XBfcRdD1LFkdmzzGHYAshPc5QFLUtS4N3m9HmB_ROLxFJUcLNRD-gJZ8_at-KYawE4ZjoyC2n3Cgk1FlJQ9R_6iN7J5mQ5GS6tiIkPgeFEg6DOQPfsOy9GnoYmqdE/s1600/screenshot.7.jpg)
- Printing the signal strength:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGcpnmpzoyiaK7KV0QT8pMwb-AIIafNtow9MyD9TDxHEohq3LBFUkIVxAeDAxOp5dPwAsgo8BhLDdOmHl7UwjJcAr3dDFNCAK3n1pzbBMo6fglPWStYOgq-ja9lKsmHURz8m1HQYchSSbE/s1600/screenshot.8.jpg)
- Printing the location:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgC2C51KvaWhC-tLK3EyT5oqjjYPVENN22jwEPtAuDsf0rF8uoOIFNZo98MrJmcVJJSE2ZZglIot-2ODS_SEpmavL4dBBoREhqwechBcXsa6nEUUh9bm4kmLcZV69Z5VtMjHZcg4XcGrCO8/s1600/screenshot.9.jpg)
4 - Sending and receiving SMS messages between a cellular phone and a modem
- Connecting the modem to the cellular network:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJRPDOACc0yfWVwlRZKoiPHmlVUC86KNgT2W1EBDJaVJ3ylaiCGj60Jop1fqGGLu7svcDj3Oi0PYxItvWsPErpBW4jJIf-xg3Xxj7EaHAgCbfMcDIBPwHjIZkOoOyJvGE8GPGL3H9nzu2E/s1600/screenshot.2.jpg)
- A new interface ppp0 (point-to-point-protocol) is created:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVQdpUlILle7FwJNUKfveVPpeNwdmHru8hhsL3d4Rsfjvbo4W9pLGXHdYbT9yFBBTpa46TNv2MbHLR7niQb1W-7jZ6YtaQb47zsFBB-EzIRm4g_6ML3g9a2hvI7f_fjZ-fU1xEiDl-Nfwt/s1600/screenshot.3.jpg)
- Checking the Internet connectivity let's see the huge replay delays of the pings, what it is understable in this kind of connection:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCEp9cFUeL9FHpTrrcUY4_laepEuQdVJFRXKkb1E28PH4Z1Q5a4bSdpTJNSX2SJDdhyphenhyphenUpB_fg3tzdCc7eaAFFb_4Y9zLQ6TvIyLupttroiswwmXhDYobu5-XYMzPmoBVp5g1B359EeOhE5/s1600/screenshot.4.jpg)
- Now, to send/receive SMS messages the cellular phone device key is required (available at the user Dashboard):
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9Cv2Zhw5uBAaMOZ9FyB9PdQN_OyTkxRdwhL-QH-DGroh6roVQA-eG8sjb5tb44t-Jtim0_L9vB-6ikunYY8JCsV6U8P2bOg6Nq9qa_JgvZd0C-wE3E_d-T4RDW71I0VlLbJ9COcbyO197/s1600/29.jpg)
- Sending a message from the modem to the phone:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLKG88ZeDw1NQFEFsBYvO-sLhOyo5DT7ptQxx5y9cq4QOynSZDlwfto5wmsZe2tCMH7UCT2Il3MrNhOzJLWJWWh4YsCCjiIKMmeHsTV9Ddm6VdDtCtRxt0fGWtV6-aP5y7SdAKd_BCgx4i/s1600/24.jpg)
- The message is successfully received at the phone:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXSlCVkGX-ImCZ6oT2-rKfAW_0KX46Lrjo-GR5_a-XDzFRk5Pz47Y4Y5z6_SxkDm1NwzNGXBMPcv88CxtOIC2lvsLF8j5y7geZoThnWKGYKSihF9Ki_8UdIxWGIsE2306rFprItKuJRR1c/s320/screenshot.19.jpg)
- Preparing the modem to receive SMSs:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgLmh8jepHQSo1eeMiV-u_maaAZL7lI3YYgWEZknVGvTJnSg9z3vs_hMANlEBDMtowarkytxTdT1TnNWvDTJa-8v8QTrWizVnuhXXR_6ZhpAOaVPmEcneZrcZ1DF5ZElAjXQmEn1npdKLJ/s1600/screenshot.16.jpg)
- The phone answers:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgW6zqiODbYhjelHHkUNZa-WxzgKN6l9LKZPvIOVVpX_3GN5qgxQAx393LOKsr-u3h2K_NH_CVGCvDZ-i5_cFDwokoOosLvAkEHE8fPyFWVznHnMoV8Yu7J4FV0CeNUA7m5oiaxBfCTEZLP/s1600/screenshot.18.jpg)
- The phone receives the message:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDSxwZb_Lh60xrAyT0zxHYr1t8uvheU3QCH3seP7jYHldtsUDbgm7lK8ItUCd0WMNjLY-GPR84-jbXSAJw_CJagBky9pgLXD_lMW2ZlA-CAMOiwu9dpBriwkMqckMrO0H9FdVpiyIJXf9S/s1600/23.jpg)
- Finally the modem can be disconnected:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizWjfiOLbrQsxRgTIO7umUq4QBUlrGQxs85ZdS5-xSu2ip1W55005Ohc1s26492FPbeVqZoROq4zc5mUx5-1hAZRIKn3izAqK6QJsEzXsx9SG7s-gfCKZymfqOswVT1ZIs237UWYUh5ChA/s1600/screenshot.6.jpg)
- The Hologram Ptython SDK allows to connect and communicate the Hologram SIM card and the Nova USB modem with other IoT platforms for cellular connectivity:
https://github.com/hologram-io
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQLBJoMGXkG0-0hh4LevGX154tOJYUUS-8BhNVS8sBySwWWWGyBeSz7PekZnOs5xKazQ883yZidaIfbt9s8dkNd4UaX9_EpJ7TuFxojdRWs_5eWV_UFzFEpHjbTkd0hBDf82rg6F3N8yfn/s400/screenshot.1.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0ij27N6z2UEgl76NNH52emaylltlF6trABF1ewgWZrzMwzAKhkqOBC1UjsGsV-pqoeGkDuPPW8qW6IldUvDBfc18qT1tmcjlMmoyu2Hxgg7uOdVdgZqMV3pbYyIL0e0qSt8oK5FLc3F7r/s400/screenshot.2.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWpjaTIZzcsO4-v-LxKKIery6KZOyB-_MX58IrvMQckv_ltTRPn1zmBXNkn4lBDIchZu6OB3aBQcythvrMvUFOtrZWbCpWnpUh1hYnbEpKQYD9SCpWvW_ZE0JTyGkWnjL21_z_PkOFzAHz/s640/screenshot.3.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhu57Th0R0C2l4f3X4suqWFl1ExT-JqiRkCtZBmr5mkflS-0LZ8ZWk0e3Wph90cr4ry1IAwSxmvTlFJxDHVbRurE5P_e8Fsy_UCT-sE_F41ttZjzZJ69QQP-CT-pYK9-48JXBGjUFbXNZN6/s400/screenshot.43.jpg)
- Installing the Hologram Python SDK to the Raspberry Pi device:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL_Of2bb573W9AFH_G6M0rUfSzs_-FG3q9lHnr8Xk3MDxtZBh9EI8UPruNunQd3L9ubDcDHdxqpPz8zRTif313ooVHLEPG4M7ahu6xTo2OCGHm0h5TD_-bSNN08BKfOrHKZb-I0FBWUl1S/s1600/screenshot.4.jpg)
..............................
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-gEELk2rkKQGYEhXAcA2YkhPoBUrX-RrhGwcnIM3hSJCRJlJ-6lOh9V4QM05Izg2KYnl3rTx-AIUAIGV0tJfVZM-NUyTtCY6G9gY_qIWvXeXMyDGNZU0I1DQ72TmTs2VsbTo6rzaXOvXp/s1600/screenshot.5.jpg)
- On next exercises this Python SDK platform will be used abundantly:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip3Ro2OQAsSZrXprvzL8OOQvSpd1fnjKVFQCse0cNCZg8zBkrqJbUm6DHl_UtIoX-yp91t_6rxnZbukJJjp6HyeJDL5QkZn9N60bnRChDVtAkWPKeAJ1o2SG1sHdhV2qtBA9CrpAABYys8/s1600/screenshot.6.jpg)
3 - Checking the functionality of the modem
- First of all, let's check that Raspberry Pi detects the modem connected to one of its USB ports:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhs_3z5jGF96VnoPpiNs2mYf13ydrDJud1zW0LShBi-fWt4QSb-yBG-z7Ipq0d2_c22tU967f-Yomr75H7iYDCQJ_nsddwjbbiJZUcLt_R6RIvovdvFqXzojJaA2xKIIObSfdBR6_mpoSol/s1600/screenshot.1.jpg)
- Accessing available ports:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTOomvESxyeMjs-ekDmRIRVIvcdBWEnOWkK3FARF0xb6PxwrBYByIVLZ_vgc49SR3Bd_YqG3MqjKAuTbJZYdpM6xio-Uj1Kl-Zq0QG2ouaZzd3rWfo9jNgYBlukHbM_PR00Nwm1iXuwJQm/s1600/screenshot.2.jpg)
- hologram command has got several options:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3HJFMYkFiRzZHCx-E7-qQSopeCb0CJMIAUXDMdrfMJlUQYINj7qFnM5qG04yG-PNxNnRm7sLAb-6UqMX7hMC1fp88XSyHM_aGCPe8zZ-sjgZSRAggKdT0lk-fL3vRgvtUUb-O6PeHZ02r/s1600/screenshot.3.jpg)
- Detecting the type of modem:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT9ihtiLRDkl3M65xukD0-_zXeQ78ZLTGkH5ovJyIzQ5g0HqOno7ZJfQc6V6Vz5osNB97LIA0XU8UIsm0unXQhsBv_llR7ih9_MFduNm8N1bCUipuVypMoltBnd0ECsIUeJ6witidjb5u_/s1600/screenshot.4.jpg)
- Printing the celullar network available:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigh7ekl0Jcri8OM_TosagA6GCRnNM3bFtlt8PkGnUS9f-wNa-3L6V1fJckY3Rlp9uCIEPcJwy9iNBTN1DDlIeJ7JIdxbyww_d2skbDimMKv4nnPn86WFInsdUeKvO49LpHj7kuCIP9_DOz/s1600/screenshot.5.jpg)
- Printing the SIM card number used with the modem:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZh_HsY_bs5iuFOW4XBfcRdD1LFkdmzzGHYAshPc5QFLUtS4N3m9HmB_ROLxFJUcLNRD-gJZ8_at-KYawE4ZjoyC2n3Cgk1FlJQ9R_6iN7J5mQ5GS6tiIkPgeFEg6DOQPfsOy9GnoYmqdE/s1600/screenshot.7.jpg)
- Printing the signal strength:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGcpnmpzoyiaK7KV0QT8pMwb-AIIafNtow9MyD9TDxHEohq3LBFUkIVxAeDAxOp5dPwAsgo8BhLDdOmHl7UwjJcAr3dDFNCAK3n1pzbBMo6fglPWStYOgq-ja9lKsmHURz8m1HQYchSSbE/s1600/screenshot.8.jpg)
- Printing the location:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgC2C51KvaWhC-tLK3EyT5oqjjYPVENN22jwEPtAuDsf0rF8uoOIFNZo98MrJmcVJJSE2ZZglIot-2ODS_SEpmavL4dBBoREhqwechBcXsa6nEUUh9bm4kmLcZV69Z5VtMjHZcg4XcGrCO8/s1600/screenshot.9.jpg)
4 - Sending and receiving SMS messages between a cellular phone and a modem
- Connecting the modem to the cellular network:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJRPDOACc0yfWVwlRZKoiPHmlVUC86KNgT2W1EBDJaVJ3ylaiCGj60Jop1fqGGLu7svcDj3Oi0PYxItvWsPErpBW4jJIf-xg3Xxj7EaHAgCbfMcDIBPwHjIZkOoOyJvGE8GPGL3H9nzu2E/s1600/screenshot.2.jpg)
- A new interface ppp0 (point-to-point-protocol) is created:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVQdpUlILle7FwJNUKfveVPpeNwdmHru8hhsL3d4Rsfjvbo4W9pLGXHdYbT9yFBBTpa46TNv2MbHLR7niQb1W-7jZ6YtaQb47zsFBB-EzIRm4g_6ML3g9a2hvI7f_fjZ-fU1xEiDl-Nfwt/s1600/screenshot.3.jpg)
- Checking the Internet connectivity let's see the huge replay delays of the pings, what it is understable in this kind of connection:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCEp9cFUeL9FHpTrrcUY4_laepEuQdVJFRXKkb1E28PH4Z1Q5a4bSdpTJNSX2SJDdhyphenhyphenUpB_fg3tzdCc7eaAFFb_4Y9zLQ6TvIyLupttroiswwmXhDYobu5-XYMzPmoBVp5g1B359EeOhE5/s1600/screenshot.4.jpg)
- Now, to send/receive SMS messages the cellular phone device key is required (available at the user Dashboard):
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9Cv2Zhw5uBAaMOZ9FyB9PdQN_OyTkxRdwhL-QH-DGroh6roVQA-eG8sjb5tb44t-Jtim0_L9vB-6ikunYY8JCsV6U8P2bOg6Nq9qa_JgvZd0C-wE3E_d-T4RDW71I0VlLbJ9COcbyO197/s1600/29.jpg)
- Sending a message from the modem to the phone:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLKG88ZeDw1NQFEFsBYvO-sLhOyo5DT7ptQxx5y9cq4QOynSZDlwfto5wmsZe2tCMH7UCT2Il3MrNhOzJLWJWWh4YsCCjiIKMmeHsTV9Ddm6VdDtCtRxt0fGWtV6-aP5y7SdAKd_BCgx4i/s1600/24.jpg)
- The message is successfully received at the phone:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXSlCVkGX-ImCZ6oT2-rKfAW_0KX46Lrjo-GR5_a-XDzFRk5Pz47Y4Y5z6_SxkDm1NwzNGXBMPcv88CxtOIC2lvsLF8j5y7geZoThnWKGYKSihF9Ki_8UdIxWGIsE2306rFprItKuJRR1c/s320/screenshot.19.jpg)
- Preparing the modem to receive SMSs:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgLmh8jepHQSo1eeMiV-u_maaAZL7lI3YYgWEZknVGvTJnSg9z3vs_hMANlEBDMtowarkytxTdT1TnNWvDTJa-8v8QTrWizVnuhXXR_6ZhpAOaVPmEcneZrcZ1DF5ZElAjXQmEn1npdKLJ/s1600/screenshot.16.jpg)
- The phone answers:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgW6zqiODbYhjelHHkUNZa-WxzgKN6l9LKZPvIOVVpX_3GN5qgxQAx393LOKsr-u3h2K_NH_CVGCvDZ-i5_cFDwokoOosLvAkEHE8fPyFWVznHnMoV8Yu7J4FV0CeNUA7m5oiaxBfCTEZLP/s1600/screenshot.18.jpg)
- The phone receives the message:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDSxwZb_Lh60xrAyT0zxHYr1t8uvheU3QCH3seP7jYHldtsUDbgm7lK8ItUCd0WMNjLY-GPR84-jbXSAJw_CJagBky9pgLXD_lMW2ZlA-CAMOiwu9dpBriwkMqckMrO0H9FdVpiyIJXf9S/s1600/23.jpg)
- Finally the modem can be disconnected:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizWjfiOLbrQsxRgTIO7umUq4QBUlrGQxs85ZdS5-xSu2ip1W55005Ohc1s26492FPbeVqZoROq4zc5mUx5-1hAZRIKn3izAqK6QJsEzXsx9SG7s-gfCKZymfqOswVT1ZIs237UWYUh5ChA/s1600/screenshot.6.jpg)