DE19k2/9k6 in a Data Engine

[parasram@ldc.uwi.tt]

Hello everyone !

        I have a Kantronics Data Engine with a DE19k2/9k6 modem operating
at 9600baud.

        The user manual for the modem states the following :
"With other radios requiring higher drive signals, place J11 on both posts,
which removes the 47k resistor. Then key the radio and adjust R18 for 3khz
deviation."  (pg.9)

My question is :
        How will I know when 3khz deviation is acquired (while adjusting
the potentiometer) ? Will I need a scope or frequency counter? Note that I
use a Yaesu FT-5100.

Thanking all in advance for the replies...