Patch 1 to 6: Implement the "+++" escape sequence detection with guard timeouts. Patch 7: Implement the Hook Control Callback into emulator. Patch 8 to 12: Implement the return to Online Data State Callback into emulator. Implement gatppp and gathdlc new APIs to resume PPP server. Patch 13 to 16: Implement gatppp and gathdlc new APIs to control PPP client with gsmdial. Patch 17 and 18 are adding a new option into gsmdial to send an escape sequence whether a PPP conection is established. The "+++" sequence can't be written using GAtChat because it is adding and '\r' character at the end of the string. I have used the write_done GAtIO CB to detect when a PPP packet is written to suspend PPP client and write "+++" on GAtIO. The GUARD_TIMEOUTS value defined into gsmdial is ruling the timing to do: +++ --> ATO0 --> +++ --> ATH0 If you want to send an escape sequence you have to use gsmdial in this way: sudo ./gsmdial -i your_inet_addr -p 12346 -b -e Guillaume Zajac (18): gat: add GAtSuspendFunc CB typedef gathdlc: add g_at_hdlc_set_suspend_function() prototype gathdlc: add mechansim to detect '+++' escape sequence gatppp: add g_at_ppp_set_suspend_function() prototype gatppp: add g_at_ppp_set_suspend_function() definition emulator: add ppp_suspend() CB and register it emulator: add AT hook_control_cb() and register it gathdlc: add g_at_resume_hdlc() prototype. gathdlc: add g_at_hdlc_resume() definition. gatppp: add g_at_ppp_resume() prototype gatppp: add g_at_ppp_resume() definition. emulator: add AT online_data_state_cb() and register it gathdlc: add prototype to suspend gathdlc externally gathdlc: add g_at_hdlc_suspend() definition gatppp: add prototype to suspend ppp server externally gatppp: add g_at_ppp_suspend() definition gsmdial: add new option to test sending escape sequence gsmdial: implement mechanism to send +++ -> ATO0 -> +++ -> ATH0 gatchat/gat.h | 1 + gatchat/gathdlc.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++++ gatchat/gathdlc.h | 7 ++ gatchat/gatppp.c | 32 ++++++++++ gatchat/gatppp.h | 5 ++ gatchat/gsmdial.c | 167 ++++++++++++++++++++++++++++++++++++++++++++-------- src/emulator.c | 100 +++++++++++++++++++++++++++++++- 7 files changed, 435 insertions(+), 29 deletions(-)