diff --git a/usr.sbin/ppp/bundle.c b/usr.sbin/ppp/bundle.c
index 0bb9c7d16388..e06517a0c7d1 100644
--- a/usr.sbin/ppp/bundle.c
+++ b/usr.sbin/ppp/bundle.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: bundle.c,v 1.6 1998/05/23 22:28:19 brian Exp $
+ *	$Id: bundle.c,v 1.7 1998/05/25 02:22:30 brian Exp $
  */
 
 #include <sys/types.h>
@@ -1450,7 +1450,7 @@ bundle_SendDatalink(struct datalink *dl, int s, struct sockaddr_un *sun)
     msg.msg_iov = iov;
     msg.msg_iovlen = niov;
 
-    if (link_fd == STDIN_FILENO && isatty(link_fd)) {
+    if (tcgetpgrp(link_fd) == getpgrp()) {
       /*
        * We can't transfer this tty descriptor.  If we do, then once the
        * session leader exits, the descriptor becomes unusable by the
@@ -1480,7 +1480,7 @@ bundle_SendDatalink(struct datalink *dl, int s, struct sockaddr_un *sun)
     /* We must get the ACK before closing the descriptor ! */
     read(s, &ack, 1);
 
-    if (link_fd == STDIN_FILENO && isatty(link_fd)) {
+    if (tcgetpgrp(link_fd) == getpgrp()) {
       /* We use `/bin/cat' to keep the tty session id */
       pid_t pid;
       int status, len, fd;
diff --git a/usr.sbin/ppp/modem.c b/usr.sbin/ppp/modem.c
index 1b7f6eeb767b..01bdab0f1e5c 100644
--- a/usr.sbin/ppp/modem.c
+++ b/usr.sbin/ppp/modem.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: modem.c,v 1.83 1998/05/23 22:24:44 brian Exp $
+ * $Id: modem.c,v 1.84 1998/05/25 02:22:37 brian Exp $
  *
  *  TODO:
  */
@@ -1051,7 +1051,7 @@ modem2iov(struct physical *p, struct iovec *iov, int *niov, int maxiov)
     timer_Stop(&p->link.ccp.fsm.StoppedTimer);
     if (p->Timer.state != TIMER_STOPPED) {
       timer_Stop(&p->Timer);
-      if (!physical_IsATTY(p) || p->fd != STDIN_FILENO)
+      if (tcgetpgrp(p->fd) == getpgrp())
         p->Timer.state = TIMER_RUNNING;	/* Special - see iov2modem() */
     }
     timer_Stop(&p->link.throughput.Timer);