PPPD connection terminated

Question

I'm using a DIGI Connectcore 6 SBC with a Telit He910 as a Modem and once or twice a day the connection hangs. This is what happens

    I/pppd    ( 1216): No response to 3 echo-requests
    I/pppd    ( 1216): Serial link appears to be disconnected.
    I/pppd    ( 1216): Connect time 10144264.4 minutes.
    I/pppd    ( 1216): Sent 273626 bytes, received 3973358 bytes.
    D/pppd    ( 1216): Script /etc/ppp/ip-down-ppp0 started (pid 10447)
    D/pppd    ( 1216): sent [LCP TermReq id=0x2 "Peer not responding"]
    I/ip-down-ppp0(10447): ip-down-ppp0 script is launched with 
    I/ip-down-ppp0(10447):  Interface   :   ppp0
    I/ip-down-ppp0(10447):  TTY device  :   /dev/ttyACM0
    I/ip-down-ppp0(10447):  TTY speed   :   115200
    I/ip-down-ppp0(10447):  Local IP    :   10.0.55.193
    I/ip-down-ppp0(10447):  Remote IP   :   10.0.55.193
    I/ip-down-ppp0(10447): cannot connect rild-ppp socket 
    I/ip-down-ppp0(10447): send  ppp-down to rild-ppp
    I/ip-down-ppp0(10447): send  ppp-down to rild-ppp end
    D/pppd    ( 1216): Script /etc/ppp/ip-down-ppp0 finished (pid 10447), status = 0x0
    D/pppd    ( 1216): sent [LCP TermReq id=0x3 "Peer not responding"]
    I/pppd    ( 1216): Connection terminated.

Here is my config file:

    defaultroute
    # lock
    noauth
    # Debug info from pppd
    debug
    #kdebug 4
    # Most phones don't reply to LCP echos
    lcp-echo-failure 3
    lcp-echo-interval 3
    # Keep pppd attached to the terminal
    # Comment this to get daemon mode pppd
    nodetach
    # The chat script (be sure to edit that file, too!)
    connect "/system/bin/chat -v -f /etc/ppp/conf-chat-swisscom"  
    # Serial Device to which the modem is connected 
    /dev/ttyACM0
    # Serial port line speed 
    115200
    dump
    # The phone is not required to authenticate 
    #noauth 
    user gprs
    name gprs
    password gprs
    # If you want to use the HSDPA link as your gateway
    defaultroute 
    # pppd must not propose any IP address to the peer 
    #noipdefault 
    ipcp-accept-local 
    ipcp-accept-remote 
    # Keep modem up even if connection fails 
    #persist 
    # Hardware flow control 
    crtscts 
    # Ask the peer for up to 2 DNS server addresses 
    usepeerdns 
    # No ppp compression 
    novj 
    nobsdcomp 
    novjccomp 
    nopcomp 
    noaccomp 
    # For sanity, keep a lock on the serial line 
    # lock 
    # Show password in debug messages 
    show-password
    linkname ppp0

I am hitting a dead end, and it's really frustrating