Thanks Dave. I'm sure that conforming to the radio manufacturer's
recommendation/opinion for the cabling and Flow Control should be one of the
first requirements before expecting the software to control the radio.
Gary - AB9M
From: Dave AA6YQ
Sent: Sunday, July 25, 2010 9:11 PM
Subject: FW: Commander
And now the fallout from ops who had Flow Control enabled but without a serial
port cable that conveys RTS and CTS (or for the Omni-VII, CTS).
From: Dave AA6YQ [mailto:firstname.lastname@example.org]
Sent: Sunday, July 25, 2010 10:05 PM
To: John Uhl
Cc: Dave Bernstein AA6YQ
Subject: RE: Commander
A long-standing defect in Commander allowed control of your Orion II, even
though the cable connecting your transceiver to your PC does not correctly
convey the RTS and CTS signals as described in the Orion II manual. This defect
was corrected in Commander 8.5.5, causing your configuration to stop working
because of the missing signals.
Here's the full story:
"Flow Control" is a mechanism that allows the software running on the
microprocessor within a transceiver to temporarily prevent Commander from
sending another command; the transceiver's software would typically do this if
it couldn't complete the current command before a new command might arrive.
Most transceivers are fast enough to not require the use of Flow Control, but
several TenTec transceivers require it, in part because their serial port is
fixed at 57,600 baud.
Flow Control requires an additional two conductors in the cable connecting the
PC serial port (or USB-to-serial adaptor) to the transceiver: RTS and CTS.
Commander is configured to use Flow Control by setting the RTS selector to
'Flow' in the "Primary CAT Serial Port" panel on the Config window's Ports tab.
There has been a long-standing defect in Commander's implementation of Flow
Control that was repaired in Commander 8.5.5: on startup, Commander would not
enable Flow Control even though its primary port RTS selector was set to
'Flow'. This went unnoticed because only TenTec radios require Flow Control,
and most of them are evidently fast enough to work correctly even when they
can't govern the rate at which Commander sends commands. It wasn't until Gary
AB9M reported that he couldn't reliably QSY his Omni-VII by scrolling his
wheeled mouse in Commander's Bandspread window that a debugging effort led
TenTec's John Henry to discover that Commander was not correctly implementing
Flow Control. This defect repair was implemented in Commander 8.5.4 and
publicly released yesterday with Commander 8.5.5.
So prior to Commander 8.5.5, having Flow Control enabled -- as was the case in
your system -- didn't actually enable Flow Control, but Commander properly
controlled your Orion II anyway. Now that the defect has been corrected,
Commander 8.5.5 correctly implements Flow Control, which means that Commander
won't send commands to your Orion II unless the serial port CTS signal is
asserted -- a signal that should be supplied by your Orion II in response to
seeing the RTS signal from your PC asserted (by Commander). I suspect that the
cable connecting your Orion II to your PC's serial port does not convey the RTS
and CTS signals. Thus Commander 8.5.5 was waiting forever for a "go ahead" from
your transceiver to send commands -- a "go ahead" that would never arrive.
Since releases of Commander prior to 8.8.5 correctly controlled your Orion II,
the quick fix was to disable primary CAT port Flow Control by changing the RTS
selector from 'Flow' to 'Off' or 'On'; I'm glad to hear that worked as
expected. The right solution would be to use a cable between your PC serial
port and Orion II that conveys the RTS and CTS signals; then you could
re-configure Commander to use Flow Control as specified in the Orion
From: John Uhl [mailto:email@example.com]
Sent: Sunday, July 25, 2010 9:02 PM
To: 'Dave AA6YQ'
Subject: RE: Commander
Set to RTS and ON. Close down Commander and presto it worked.
Dave, you are genius. Thanks for the help.
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