After about 6secs, there is Modem Hangup on the AOSP target device. There are exchanges of data where data is sent from the Ubuntu/Linux device and received on AOSP target device but no data is sent from the AOSP target device. I have played around with my options file; adjusting the baud rate, MTU/MRU, compression is disabled, flow control and behavior settings etc. But, it did not help with resolving the issue. The options file for Ubuntu/Linux below: # UART interface and baud rate /dev/ttyUSB0 115200 #silent nolock kdebug 7 # Do not support ipv6 noipv6 # Flow control and behavior settings xonxoff # Enable software flow control (XON/XOFF) nodetach # Prevents ppd from running in the backgroud. O/Ps logs to the terminal debug # Enable detailed logging for debugging purposes nocrtscts # Disable hardware flow control (no RTS/CTS handshaking) noauth # No authentication (open connection) dump # prints out all the option values # Serial communication settings local # Do not use modem control lines; assume a direct serial connection # Compression settings (disable all forms of compression) noccp # Disable CCP (Compression Control Protocol) nobsdcomp # Disable BSD compression nodeflate # Disable Deflate compression novj # Disable Van Jacobson style TCP/IP header compression # Connection persistence persist # Automatically attempt to keep the connection alive if it drops # Transmission Settings mtu 128 # Set the Maximum Transmission Unit mru 128 # Set the Maximum Receive Unit # IP addressing and routing settings nodefaultroute # Do not add a default route through the PPP connection noipdefault # Do not request a specific IP address from the peer 10.0.0.1:10.0.0.2 # Local IP:Remote IP # IPCP settings ipcp-accept-remote # Accept the IP address provided by the peer #ipcp-accept-local maxfail 0 # Link Control Protocol (LCP) settings lcp-echo-interval 0 # Disable LCP echo requests (used to detect dead connections) lcp-echo-failure 0 # Disable LCP echo failure detection the options file on AOSP Target device # UART interface and baud rate /dev/ttyMSM0 115200 kdebug 7 # Do not support ipv6 noipv6 # Flow control and behavior settings xonxoff # Enable software flow control (XON/XOFF) nodetach # Prevents ppd from running in the backgroud. O/Ps logs to the terminal debug # Enable detailed logging for debugging purposes nocrtscts # Disable hardware flow control (no RTS/CTS handshaking) noauth # No authentication (open connection) dump # prints all the option value # Serial communication settings local # Do not use modem control lines; assume a direct serial connection nolock # Compression settings (disable all forms of compression) noccp # Disable CCP (Compression Control Protocol) nobsdcomp # Disable BSD compression nodeflate # Disable Deflate compression novj # Disable Van Jacobson style TCP/IP header compression # Connection persistence persist # Automatically attempt to keep the connection alive if it drops # Transmission Settings mtu 128 # Set the Maximum Transmission Unit mru 128 # Set the Maximum Receive Unit # IP addressing and routing settings nodefaultroute # Do not add a default route through the PPP connection noipdefault # Do not request a specific IP address from the peer 10.0.0.2:10.0.0.1 # Local IP : Remote IP # IPCP settings ipcp-accept-remote # Accept the IP address provided by the peer # Link Control Protocol (LCP) settings lcp-echo-interval 0 # Disable LCP echo requests (used to detect dead connections) lcp-echo-failure 0 # Disable LCP echo failure detectioin Error Logs on AOSP Target: using channel 932 Using interface ppp0 Connect: ppp0 <--> /dev/ttyMSM0 sent [LCP ConfReq id=0x3 <mru 128> <asyncmap 0xa0000> <magic 0xc875a15e> <pcomp> <accomp>] rcvd [LCP ConfReq id=0x3 <mru 128> <asyncmap 0xa0000> <magic 0x184ddd9> <pcomp> <accomp>] sent [LCP ConfAck id=0x3 <mru 128> <asyncmap 0xa0000> <magic 0x184ddd9> <pcomp> <accomp>] rcvd [LCP ConfAck id=0x3 <mru 128> <asyncmap 0xa0000> <magic 0xc875a15e> <pcomp> <accomp>] sent [IPCP ConfReq id=0x3 <addr 10.0.0.2>] rcvd [IPCP ConfReq id=0x3 <addr 10.0.0.1>] sent [IPCP ConfAck id=0x3 <addr 10.0.0.1>] rcvd [IPCP ConfAck id=0x3 <addr 10.0.0.2>] local IP address 10.0.0.2 remote IP address 10.0.0.1 Modem hangup Connect time 0.1 minutes. Sent 0 bytes, received 1276 bytes. Connection terminated. Any inputs to resolve the issue would be helpful. Thanks, Devesh
