service_call serviceName ([requestMsg] [[,] replyMsg]) 
	[callOption]...

...
@app()->hdl_exception = "exc_hand"
@app()->hdl_jif_changed = "jchhandc"

client_init client last_name user "Customer" \
	notification poll
if ((@app()->tp_severity) > TP_WARNING)
{
	// initiating a connection was unsuccessful
	message = @app()->tp_exc_msg
	msg quiet message
	...
	return 0
}

// validate PIN given by the customer
service_call service "VAL_PIN" ({last_name, pin}, \
	{message, owner_ssn = user_info})

// check if validation was not successful
if ((@app()->tp_severity > TP_WARNING) || \
	 (@app()->tp_svc_outcome == TP_FAILURE))
{
	msg quiet message
	client_exit
	...
}
...
return 0
}