$ cat ppp.log.uart
Script /usr/sbin/chat -v -f /etc/ppp/chat-4g finished (pid 657), status = 0x0
Serial connection established.
using channel 7
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS5
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x82de0ac6> <pcomp> <accomp>]
rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xf9919212> <pcomp> <accomp>]
sent [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xf9919212> <pcomp> <accomp>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x82de0ac6> <pcomp> <accomp>]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [IPCP ConfReq id=0x1]
sent [IPCP ConfNak id=0x1 <addr 0.0.0.0>]
rcvd [IPCP ConfRej id=0x1 <addr 0.0.0.0>]
sent [IPCP ConfReq id=0x2 <addrs 0.0.0.0 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [IPCP ConfReq id=0x2]
sent [IPCP ConfAck id=0x2]
rcvd [IPCP ConfRej id=0x2 <addrs 0.0.0.0 0.0.0.0>]
sent [IPCP ConfReq id=0x3 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [IPCP ConfNak id=0x3 <ms-dns1 193.41.60.16> <ms-dns2 193.41.60.15>]
sent [IPCP ConfReq id=0x4 <ms-dns1 193.41.60.16> <ms-dns2 193.41.60.15>]
rcvd [IPCP ConfAck id=0x4 <ms-dns1 193.41.60.16> <ms-dns2 193.41.60.15>]
Could not determine local IP address
Connect time 0.1 minutes.
Sent 94 bytes, received 64 bytes.
sent [IPCP TermReq id=0x5 "Could not determine local IP address"]
sent [IPCP TermReq id=0x6 "Could not determine local IP address"]
rcvd [IPCP TermReq id=0x6 "Could not determine local IP address"]
sent [IPCP TermAck id=0x6]
rcvd [IPCP TermAck id=0x6]
sent [LCP TermReq id=0x2 "No network protocols running"]
rcvd [LCP TermReq id=0x2 "No network protocols running"]
sent [LCP TermAck id=0x2]
rcvd [LCP TermAck id=0x2]
Connection terminated.

$ cat ppp.log.usb
Script /usr/sbin/chat -v -f /etc/ppp/chat-4g finished (pid 546), status = 0x0
Serial connection established.
using channel 1
Using interface ppp0
Connect: ppp0 <--> /dev/ttyACM0
rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x96a24aa4> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xb168a46a> <pcomp> <accomp>]
sent [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x96a24aa4> <pcomp> <accomp>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xb168a46a> <pcomp> <accomp>]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [IPCP ConfReq id=0x1]
sent [IPCP ConfNak id=0x1 <addr 0.0.0.0>]
rcvd [IPCP ConfNak id=0x1 <addr 10.247.92.74> <ms-dns1 193.41.60.16> <ms-dns2 193.41.60.15>]
sent [IPCP ConfReq id=0x2 <addr 10.247.92.74> <ms-dns1 193.41.60.16> <ms-dns2 193.41.60.15>]
rcvd [IPCP ConfReq id=0x2 <addr 10.247.92.74>]
sent [IPCP ConfAck id=0x2 <addr 10.247.92.74>]
rcvd [IPCP ConfAck id=0x2 <addr 10.247.92.74> <ms-dns1 193.41.60.16> <ms-dns2 193.41.60.15>]
not replacing default route to eth0 [192.168.1.1]
local  IP address 10.247.92.74
remote IP address 10.247.92.74
primary   DNS address 193.41.60.16
secondary DNS address 193.41.60.15
Script /etc/ppp/ip-up started (pid 551)
Script /etc/ppp/ip-up finished (pid 551), status = 0x0


$ cat chat-4g
ABORT    "BUSY"
ABORT    "ERROR"
ABORT    "NO ANSWER"
ABORT    "NO CARRIER"
ABORT    "NO DIALTONE"
''       ATZ
''       ATZ
OK       AT+CGDCONT=1,"IP","www.ab.kyivstar.net"
OK       ATDT*99***1#
'ATD' ^M
'' ^M


$ cat peers/4g
/dev/ttyS5 115200
#/dev/ttyACM0 115200
nobsdcomp
nodeflate
connect '/usr/sbin/chat -v -f /etc/ppp/chat-4g'
noauth
#noipdefault
usepeerdns
defaultroute
debug
#nodetach
persist
## new ###
novj
nocrtscts
#local
lock
logfile /var/log/ppp.log
user ipgrs
#mru 512
#mtu 512