[RTTY] FW: Icom IC7600 and MMTTY

Gary E. Jones garyejones at cmaaccess.com
Mon Oct 12 06:29:51 PDT 2009

I appreciate the information and will look into it further. Since there do
appear to be some people in here that are using the 7600 radio, do you know
the answer to my second question... Can I keyboard CW directly from the ICOM
USM keyboard connected to the radio in a similar way to what you can do with


                     Gary    W5FI 


-----Original Message-----
From: rtty-bounces at contesting.com [mailto:rtty-bounces at contesting.com] On
Behalf Of Dave AA6YQ
Sent: Sunday, October 11, 2009 10:09 PM
To: Gary E. Jones
Cc: Dave Bernstein AA6YQ; rtty at contesting.com
Subject: Re: [RTTY] FW: Icom IC7600 and MMTTY

>>>AA6YQ comments below

-----Original Message-----
From: Gary E. Jones [mailto:garyejones at cmaaccess.com] 
Sent: Sunday, October 11, 2009 8:38 PM
To: 'Dave AA6YQ'
Subject: RE: [RTTY] Icom IC7600 and MMTTY

I do not yet own an ICOM IC-7600 transceiver but am seriously close to
making the purchase. Therefore, I am not absolutely positive about this, but
the manual indicates right at the start that RTTY in the 7600 is FSK, not
AFSK. It is the understanding of a good friend of mine who owns one that the
situation is the opposite of what is stated below... that is if you do want
to run AFSK that you need to enable the signal out on the back panel and you
can feed it to an external AFSK sound card interface. 

>>>Your friend is incorrect. You can transmit RTTY with the IC-7600 in
either FSK or AFSK. I have made an RTTY QSO with an IC-7600 using AFSK, with
nothing but a USB cable connecting the transceiver to my laptop running
MMTTY. I also successfully tested this configuration with WinWarbler, which
uses MMTTY as a "RTTY engine".

>>>The IC-7600 includes a Universal Serial Bus (USB) interface that when
connected to your PC by a standard A/B USB cable 

 1. emulates a soundcard, allowing an application on your PC to transmit
audio to your IC-7600, and receive audio from your IC-7600

 2. conveys CI-V instructions from an application on your PC to your IC-7600
-- including instructions that switch the tranceiver between RX and TX

>>>Using the USB interface to transmit audio to your IC-7600 (AFSK
transmission) requires placing your IC-7600 in DATA mode, which is different
from RTTY mode; for example, the IC-7600's RTTY-optimized Twin Peak Filter
is not available in DATA mode.

>>>If you are using a RTTY application like MMTTY that can issue CI-V
instructions for RX-TX switching, and if you are ok with having your IC-7600
in DATA mode rather than RTTY mode, then the USB connection between your PC
and IC-7600 is all that's required for RTTY operation.

>>>If you wish to transmit in FSK with MMTTY, you can still use the USB
connection deacribed above for receiving audio and for RX-TX switching, but
you'll need an additional serial port on your PC with a signal (TxD, RTS, or
DTR) that drives an external RS232-to-TTL level converter connected to pin 1
(RTTY) of your IC-7600's ACC-1 connector; this signal switches your IC-7600
between mark and space when transmitting. If you use an USB-to-serial-port
adaptor for this serial port, you should use MMTTY's EXTFSK "helper
application" so that RTS or DTR can be used, as many USB-to-serial-port
adaptors cannot generate the required signal on TxD.

>>>If the RTTY application you're using cannot perform RX-TX switching by
issuing the appropriate CI-V commands, then you'll need a serial port signal
that drives an RS232-to-TTL level converter connected to pin 3 (SEND) of
your IC-7600's ACC-1 connector or ACC-2 connector.


         Dave, AA6YQ

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