text: /*
   * Copyright (c) 2000 Hellmuth Michaelis. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *---------------------------------------------------------------------------
   *
   *	i4b_l1lib.c - general useful L1 procedures
   *	------------------------------------------
   *
   *	$Id: i4b_l1lib.c,v 1.3 2000/05/29 15:41:41 hm Exp $
   *
   * $FreeBSD: src/sys/i4b/layer1/i4b_l1lib.c,v 1.3.2.1 2001/08/10 14:08:36 obrien Exp $
   * $DragonFly: src/sys/net/i4b/layer1/i4b_l1lib.c,v 1.6 2006/12/22 23:44:55 swildner Exp $
   *
   *      last edit-date: [Mon May 29 15:24:21 2000]
   *
   *---------------------------------------------------------------------------*/
  
  #include <sys/param.h>
  #include <sys/systm.h>
  
  
  #include <net/i4b/include/machine/i4b_ioctl.h>
  #include <net/i4b/include/machine/i4b_trace.h>
  
  #include "i4b_l1.h"
  
  #define TEL_IDLE_MIN (BCH_MAX_DATALEN/2)
  
  /*---------------------------------------------------------------------------*
   *	telephony silence detection
   *---------------------------------------------------------------------------*/
  int
  i4b_l1_bchan_tel_silence(unsigned char *data, int len)
  {
  	int i = 0;
  	int j = 0;
  
  	/* count idle bytes */
  	
  	for(;i < len; i++)
  	{
  		if((*data >= 0xaa) && (*data <= 0xac))
  			j++;
  		data++;
  	}
  
  #ifdef NOTDEF
  	kprintf("i4b_l1_bchan_tel_silence: got %d silence bytes in frame\n", j);
  #endif
  	
  	if(j < (TEL_IDLE_MIN))
  		return(0);
  	else
  		return(1);
  
  }
  