Not necessarily. . .
The Delay function of the Model 318 is only important for CW mode.
It has no functionality in SSB mode.
This is the primary function of the Model 318.
However . . . there are other features of the Model 318 which are
interesting for SSB operators, at least if you own an Eagle transceiver.
Scenario 1: You want to run PSK using a Model 712 AND you also run CW or
SSB using a linear amplifier:
The Eagle has a single DIN Accessory jack on the back panel.
It is used for connecting the PSK audio signals and it is also used for
controlling the T/R relay of the linear amp.
If you want to work PSK using the Model 712 Sound Card Adapter, you simply
plug it into this jack.
When you are working other modes and want to use a linear, you will need to
remove the Model 712 plug and plug in an 8-Pin DIN plug, in order to be able
to key the external linear with the Eagle.
Using the Model 318, you can connect the 318 to the Eagle and connect the
712 to the 2nd DIN jack on 318.
The 318 has a separate RCA phono jack for connecting the relay control line,
so you connect the amp's relay cable to this jack and leave the 712
connected to the 318. They work independently of each other.
Scenario 2: You wish to control the Eagle with an external PTT switch such
as a foot switch.
In this case you also connect the Model 318 to the Eagle's Accessory jack,
and you connect your foot switch to the 318's "ACCY" (RCA phono) jack on the
rear panel. You can also have the 712 connected at the same time, as well
as the linear control line.
There are probably other scenarios, but these are the first two which come
TenTec mailing list