Serial Cable » History » Version 5
vogelchr, 02/19/2016 10:48 PM
Added hints and warnings.
1 | 1 | laforge | |
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2 | 5 | vogelchr | The Calypso phones typically all have a serial port @ 3.3V levels on the 2.5mm earphone jack. |
3 | 1 | laforge | |
4 | 3 | laforge | Those cables are sometimes called ''T191 unlock cable''. |
5 | 1 | laforge | |
6 | 3 | laforge | You can either buy ready-made cables, e.g. at: |
7 | 1 | laforge | |
8 | 3 | laforge | * [https://www.akku-king.net/_py_Handyzubehoer-Datenkabel-USB-Motorola-USB-Datenkabel-fuer-Motorola-T191-C113-C113a-C114-C115-C115i-C116-C117-C118-C119-C121-C122-C123-C136-C139-C140-C155-C156/a-20104991/ akku-king.net] |
9 | * [http://www.dealextreme.com/details.dx/sku.14664 dealextreme.com] RS232, not USB variant |
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11 | Or you can build it yourself (detailed instructions can be found on the net, search for "t191 unlock cable" or the like). |
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13 | 4 | laforge | * TxD is at the tip of the plug (PC to Device) |
14 | * RxD is at the middle contact (Device to PC) |
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15 | 1 | laforge | * GND is the outer contact |
16 | 5 | vogelchr | |
17 | == Hints and Warnings == |
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19 | * If you don't use a 3.3V (low voltage TTL, LVCMOS) serial port you can fry your phone! (internally, it connects to the IO-pins of the baseband processor which run at 2.8V). '''Don't connect directly to your PCs serial port (running at +/- 12V!).''' |
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20 | * If your development system is virtualized (runs inside VMware, Virtualbox, Parallels...) the connections can be unreliable (the loader protocol is timing critical). |
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21 | * Your safest bet is a USB cable with a FTDI- or Prolific chip (FTx232, PL2303) configured for operation at 3.3V connected to a machine running Linux natively. |