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This web page is no longer maintained. Information presented here exists only to avoid breaking historical links.
The Project stays maintained, and lives on: see the Linux-HA Reference Documentation.
To get rid of this notice, you may want to browse the old wiki instead.

1 February 2010 Hearbeat 3.0.2 released see the Release Notes

18 January 2009 Pacemaker 1.0.7 released see the Release Notes

16 November 2009 LINBIT new Heartbeat Steward see the Announcement

Last site update:
2017-12-11 23:01:27

Serial Cable for Linux-HA (heartbeat)

Heartbeat uses CTS and RTS for flow control. So, you'll need a null modem cable which runs both CTS and RTS through properly.

On such a cable, CTS on one is connected to RTS and the other end -- and vice versa.

You need at least 7 wires run from one end to the other end

Your cable ought to be wired up a lot like this:

 near end    far end
      TR<---->CD+DSR
      TD<---->RD
     CTS<---->RTS
  CD+DSR<---->TR
      RX<---->TX
     RTS<---->CTS
     GND<---->GND

DO NOT connect TR at one end to CD/DSR at the same end.

DO NOT connect CTS to RTS at the same end of the cable.

If your cable passes the 'cat' test, but doesn't work with heartbeat, then there's about a 90% chance either it doesn't do anything with CTS and RTS at all, or it simply loops them around locally within the connectors, and doesn't pass them from one end of the cable to the other.

Neither arrangement will work.

See Also

Null modem pinout diagrams.