[TenTec] Omni VI FSK

[Gary]

I'm trying to send True FSK with my Omni VI Opt. 3 but haven't had much
luck.

I am running MMTTY on a PC with Windows 8.1 and a Startech FTDI to split up
a USB port.  I have been using the Startech for other things and it has
worked well. The transceiver is a TenTec Omni VI Opt 3.  I have run FSK
with it before.

MMTTY setup:  Ver 1.68A  Receives fine.
TX & FSK = EXTFSK/Normal
MISC = Com-TXD
When I try to transmit I get PTT but just a single tone, no diddle.

I have read that FSK normally uses +15 and -15 but I'm only get +6 and -6
volts.
The standard for using FSK with an Omni VI is to run pin 3 TXD and pin 5
ground with a 1K ohm resistor in the TXD connection to the serial port.

Does anyone have an idea what is going on and what I'm doing wrong

73,  Gary N2UM