TISOFT 7.1 to SIMATIC 555: Serial COM Setup on Windows XP

Complete field guide to establishing reliable serial communication between TISOFT 7.1 (TI505.BAT) and a SIMATIC 555 PLC when migrating from pure DOS to Windows XP, including shortcut property tuning, COM port setup, baud rate matching, and a verification matrix.

1. Overview of the TI505 to SIMATIC 555 Communication Path

The TI 505 series (marketed by Siemens as SIMATIC 555 after the 1991 acquisition of Texas Instruments Industrial Systems) was originally programmed with a DOS-hosted environment called TISOFT. The default launcher, TI505.BAT, was written for MS-DOS or a true DOS session and expects direct, low-level access to a physical COM port. Windows XP does not provide raw DOS, but it does ship a 16-bit command processor (COMMAND.COM) and a 32-bit console (cmd.exe) that can host the legacy executable when three conditions are met:

• The COM port is bound to a real RS-232 UART or a USB-to-serial adapter emulating a 16550-compatible UART.
• The Windows XP console shortcut that launches TI505.BAT is configured with screen geometry (80 x 24) and buffer sizes that match what the legacy TISOFT runtime expects.
• The host COM port baud rate exactly matches the baud rate configured on the PLC NIM (Network Interface Module) port.

TISOFT versions 6.3 through 7.1 are the final releases that support this DOS-style startup path on Windows XP. The authoritative reference is entry 17518681 in the legacy Siemens Product Support database. Sections 1.4 and 1.5 discuss installing TISOFT under Windows 95/98/XP and launching it from a desktop shortcut or from the command line. The configuration sequence below has been validated on DELL M70 and DELL 4300 laptops running Windows XP SP2 and SP3, communicating to a SIMATIC 555 over a physical COM1 port.

2. Prerequisites

2.1 Hardware

• PC or industrial workstation running Windows XP SP2 or SP3.
• One available COM1 or COM2 port. On a laptop, use a USB-to-serial adapter based on a 16550-compatible chipset (FTDI FT232, Prolific PL-2303, or equivalent). The adapter must enumerate as COM1 or COM2 in Device Manager — renumbering to COM1/COM2 in advanced port properties is acceptable.
• Null-modem serial cable. For most NIMs (505-COM, 505-CP2572, 505-CP2702), the wiring uses a 9-pin D-sub with TX/RX crossed, RTS/CTS crossed, and DTR/DSR crossed, plus signal ground.
• SIMATIC 555 / TI 505 CPU with a serial-capable NIM and known configuration key for the communication port.

2.2 Software

• TISOFT 6.3, 6.5, 7.0, or 7.1 installed under a known path, e.g. C:\TISOFT71.
• Verified presence of TI505.BAT in the installation directory.
• Local Administrator rights on the XP workstation to modify COM port properties and shortcut properties.

2.3 Reference documentation

• Siemens entry 17518681 — TISOFT Manual (v6.3 to v7.1).
• The Siemens Industry Online Support portal for the SIMATIC 555 / TI 505 product tree.

3. Identifying and Verifying the COM Port

Before launching TISOFT, the host COM port must be physically identified and reserved. The TISOFT 7.1 runtime only sees a small set of legacy COM numbers and does not gracefully handle COM3 and above on all builds.

1. Inspect the back of the workstation. A physical DB-9 male connector labeled COM1 or COM2 on the chassis is the preferred port.
2. Open Start → Settings → Control Panel → System → Hardware → Device Manager and expand Ports (COM & LPT). The actual enumerated COM number is shown in parentheses — on some OEM machines a single physical port is shipped as COM2 even when labeled COM1.
3. If using a USB-to-serial adapter, plug the adapter in first, allow enumeration, then right-click the new USB Serial Port entry and choose Properties → Port Settings → Advanced. Set the COM port number to 1 or 2.
4. Record the final COM number used — it must be hard-coded into the TISOFT shortcut target (see Section 5).

4. Installing TISOFT 7.1 on Windows XP

1. Insert the TISOFT 7.1 installation media (CD or mounted ISO).
2. Run SETUP.EXE from the root of the media. Accept the default installation directory (C:\TISOFT71) unless corporate standards dictate otherwise.
3. When prompted for the workstation type, choose Standalone PC. The Networked option requires a separate license server and is out of scope for the DOS-style local launch path.
4. When prompted for the communication port, select the COM number you reserved in Section 3.
5. Confirm that TI505.BAT and TI505.EXE are present in the installation root. If TI505.BAT is missing, copy the version shipped in the SUPPORT subfolder of the media.

5. Creating the TISOFT 7.1 Shortcut with the Correct Properties

On Windows XP, TI505.BAT must be launched from a shortcut (or from a customized COMMAND.COM console) with explicit console properties. The defaults of cmd.exe are too large and the default buffer counts are too high, which can cause TISOFT to redraw slowly when in online status mode.

5.1 Create the shortcut

1. Right-click on the desktop and select New → Shortcut.
2. When prompted for the location of the item, enter the full path to TI505.BAT and append the COM number as a positional argument. Use one of the canonical targets below:

Passing the COM number as the trailing argument to TI505.BAT is what tells TISOFT which port to open. Forgetting the trailing digit is the single most common reason for a “communication timeout” message at first go-online.

5.2 Configure the Options tab

1. Right-click the new shortcut and choose Properties.
2. Open the Options tab.
3. Set Buffer size = 1.
4. Set Number of buffers = 1.

This minimizes the XP console scrollback and forces the legacy runtime to redraw the status display directly, dramatically improving online responsiveness. Higher values will work, but online polling in status mode becomes visibly sluggish on the SIMATIC 555.

5.3 Configure the Layout tab

1. Open the Layout tab.
2. Set Screen buffer size width to 80 and height to 300 (or any small value — the width is what matters).
3. Set Window size width to 80 and height to 24.
4. Clear the “Let system position window” checkbox only if a specific window placement is required.

An 80 x 24 window exactly matches the legacy DOS text mode that TISOFT’s character-based UI was authored against. Other geometries (e.g. 132 columns, 50 rows) are known to corrupt TISOFT menu borders on some Windows XP builds.

5.4 Configure the Font tab

1. Open the Font tab.
2. Select Raster Fonts and a size of 8 x 12. Lucida Console or Consolas are also acceptable but must not be a TrueType variable-pitch font.

5.5 Configure the Screen / Colors tabs (optional)

For ease of long sessions, switch the Screen Background to white and the Screen Text to black on the Colors tab. TISOFT was designed for high-contrast terminals; the default XP console palette produces eye fatigue during extended online monitoring.

6. Starting TISOFT from the Windows XP Command Prompt

If the shortcut is not desired, or if the technician wants to keep the legacy MS-DOS feel, TISOFT can be started from a customized COMMAND.COM window.

1. Create a new desktop shortcut to %SystemRoot%\system32\command.com.
2. On the Shortcut tab, set Start in to the TISOFT installation directory (e.g. C:\TISOFT71).
3. Apply the same Options, Layout, and Font tab settings as in Section 5.
4. Double-click the shortcut. A 16-bit DOS prompt opens.
5. At the C:\TISOFT71> prompt, type TI505 1 (or TI505 2) and press Enter. TISOFT launches inside the 16-bit console window.

This method is functionally identical to launching the shortcut. It is preferred for technicians who need to issue additional batch commands (e.g. DIR to verify project files) before starting TISOFT.

7. Matching the COM Port and PLC Baud Rate

If the host COM port and the PLC NIM port do not agree on the baud rate, TISOFT will report a “communication timeout” the moment the operator presses F2 Go Online. Both sides must be configured identically; the data format is fixed by TISOFT at 8 data bits, no parity, 1 stop bit (8-N-1).

7.1 Host side (Windows XP)

1. Open Device Manager → Ports (COM & LPT) → <COMn> → Properties → Port Settings.
2. Set Bits per second to the same value as the PLC.
3. Set Data bits to 8, Parity to None, Stop bits to 1, and Flow control to Hardware (RTS/CTS). If the NIM does not support hardware handshaking, set Flow control to None and use a 3-wire cable (TX, RX, GND only).
4. Click Advanced and confirm the COM port number. Set BM Fails to modem, Discard buffers, and Enable legacy Plug and Play detection according to site policy. None of these are mandatory for TISOFT.

7.2 PLC side (SIMATIC 555 NIM)

On a 505-COM or CP2572 NIM, the serial port parameters are part of the COMM or PORT configuration word in the PLC program (commonly V-memory location V400 for port 1, V401 for port 2, depending on the CPU). The value is a 4-digit hex constant. Common baud rate encodings used in the TI 505 family are listed in Table 4.

8. Verifying the Cable and Hardware Path

Before launching TISOFT, the integrity of the cable and the NIM should be confirmed. TISOFT 7.1’s online status is not a useful diagnostic for this purpose; a faster check is PLC Workshop for Siemens 505, a 32-bit Windows package that is fully program-compatible with TISOFT and can confirm the COM / NIM handshake in a few seconds.

8.1 Cable pinout (PC DB-9 ↔ 505 NIM DB-9)

8.2 Loopback test

1. Disconnect the cable from the PLC.
2. Short pins 2 and 3 on the PC end of the cable (TX to RX).
3. Open a terminal program (HyperTerminal in XP works) and type characters. Each typed character should echo back. If not, the cable or COM port is bad.
4. Reconnect to the PLC and re-test using PLC Workshop in “Test Connection” mode.

9. Going Online and Verifying the Link

1. Double-click the TISOFT shortcut. The TISOFT main menu appears in the 80 x 24 console window.
2. Press F2 (Online). TISOFT sends a poll to the configured COM port and waits for a response from the NIM.
3. If the baud rate and cable are correct, TISOFT reports the controller model, firmware revision, and program name within 2–5 seconds at 19200 baud.
4. Press F4 (Status) to enter live status mode. The 505’s I/O, V-memory, and timer/counter values should refresh at roughly 1 Hz at 9600 baud, 2 Hz at 19200 baud.
5. Press ESC to exit online mode before closing the window.

10. TISOFT Command-Line Reference

The TI505.BAT wrapper accepts a small set of positional and switch arguments. The most useful for field use are listed below. Verify against the local copy of entry 17518681.

Example: to connect to a NIM at 9600 baud on COM2 with verbose logging, use C:\TISOFT71\TI505.BAT 2 /B=9600 /P.

11. Troubleshooting Matrix

12. Field-Proven Configuration Notes

The following field observations are derived from validated deployments of TISOFT 7.1 on Windows XP against a range of SIMATIC 555 / TI 505 controllers.

• At 19200 baud, keep the serial cable under 15 m (50 ft). Above 15 m, drop to 9600 baud or use a 505-NIM with an RS-422 port and an RS-422 cable, which can run reliably to 1200 m (4000 ft) at 19200 baud.
• If a USB-to-serial adapter is required on an XP machine, FTDI-based adapters are significantly more stable than Prolific PL-2303 units in long online sessions. Disable Windows XP’s USB selective suspend for the adapter’s hub port in Power Management to avoid spontaneous disconnects.
• TISOFT 7.1 will not start under a 64-bit operating system. The shortcut procedure in this article applies only to Windows XP 32-bit SP2/SP3 and, with some limitations, Windows 2000 SP4.
• If you must decommission the XP workstation, capture the exact TI505.BAT, TI505.EXE, and any project files (*.PRG, *.DAT) into an archive — TISOFT 7.1 is no longer distributed by Siemens, and replacement media is scarce.
• The PLC Workshop for Siemens 505 trial (Fast-Soft) is a 32-bit Windows package and installs on XP, Windows 7, and Windows 10. Use it to confirm cable integrity and NIM baud before deep-troubleshooting TISOFT itself.

13. Verification Checklist Before Returning the Station to Service

1. Double-click the TISOFT shortcut and confirm the window opens at 80 x 24 with a high-contrast palette.
2. Press F2. The PLC model and firmware appear within 5 seconds.
3. Press F4. I/O and V-memory values update in real time.
4. Force a write to a non-critical V-memory location (e.g. V100) from TISOFT and confirm the value persists after exiting and re-entering online mode.
5. Close TISOFT, wait 10 seconds, and re-launch. Go online succeeds without restarting Windows.
6. Document the baud rate, COM number, NIM type, and cable inventory code on the workstation for the next shift.

14. Frequently Asked Questions