At flr, near and far, crontab will now run rserial to send a "hb" followed by a CRNL to the base mote every 4 hours. at 00:00 UTC, 04:00 UTC, etc:
0 */4 * * * echo "hb"$'\r'$'\n' | rserial /dev/ttyS1 localhost
The base motes are on ttyS2 at flr, ttyS1 at near and ttyS7 at far.