My file looks like this:
[Unit]
Description=freeswitch
After=syslog.target network.target local-fs.target
[Service]
; service
Type=forking
PIDFile=/usr/local/freeswitch/run/freeswitch.pid
PermissionsStartOnly=true
ExecStartPre=/bin/mkdir -p /usr/local/freeswitch/run
ExecStartPre=/bin/chown freeswitch:freeswitch /usr/local/freeswitch/run
ExecStart=/usr/bin/freeswitch -ncwait -nonat
TimeoutSec=45s
Restart=always
; exec
WorkingDirectory=/usr/local/freeswitch/run
User=freeswitch
Group=freeswitch
LimitCORE=infinity
LimitNOFILE=100000
LimitNPROC=60000
;LimitSTACK=240
LimitRTPRIO=infinity
LimitRTTIME=7000000
IOSchedulingClass=realtime
IOSchedulingPriority=2
CPUSchedulingPolicy=rr
CPUSchedulingPriority=89
UMask=0007
[Install]
WantedBy=multi-user.target