Your Kenwood TS-440S HF Transceiver MUST have the IC-10 Option (IC-54, IC-55) installed.The internal modifications consist of the installation of a pair of chips. These are shown in the schematics as IC 54 and IC 55, and install easily into sockets already present in the radio, on the back of the control unit circuit board.
These chips can be bought, with instructions, as the IC-10 Interface Kit from aftermarket retailers; they can also be bought via mail order, or at any good electronics store:
IC 54 is a uPD-8251-AC Serial Communications Interface IC.
Commonly called an 8251A
IC 55 is a TC-4040-BP 12 Stage CMOS Divider IC
Commonly called a 4040Installation of these chips enables an ASCII interface (TTL levels).
This interface is accessible through the 6-pin DIN connector ACC-1 on the rear of the unit. Though this may be connected directly to certain computers, or through certain interface cards, most users will need the addition of an outboard converter box to connect to the more common RS232C port. With the IC-10 interface, or equivalent, installed, the output at ACC-1 is as follows:
Signals are at TTL levels, inverted (UART, NOT RS-232)
Baud rate is 4800 (1200 Opt.)
Format is ASCII Serial; 1 Start, 8 Data, 2 Stops
The Baud rate may be changed to 1200 Baud by removing jumper W50 and installing a jumper from the left pad to the center pad as viewed from the front of the radio.
NEXT, you need to purchase a USB to Kenwood 6-pin Cable from known dealer.
Cables with the FTDI chipset (USB) are PREFERRED.
I am slow to understand this technology.
Amateur Radio is a STEM (Science, Technology, Engineering, Mathematics) hobby.SEEK a Dealer, Local Club, or a Technically Competent Amateur for assistance.