MANAGING YOUR COM PORTS FOR COMMUNICATIONS Without a connection between your handheld and your PC, a HotSync operation will not occur and the synchronization of your data between your handheld and your PC will not take place. There are a wide variety of reasons for difficulties in establishing a serial connection between a handheld and a PC. This document provides some background and solutions for the most common reasons. For a successful HotSync synchronization between your handheld and PC, you must have an available COM (also known as a serial) port attached to a serial socket on your PC. The nature of the PC results in subtle interactions between programs running in the background, especially those accessing the COM (communications) ports. Inter-computer communication adds an additional dimension to these problems. The combination of these factors results in a variety of conditions that can make communication difficult to establish. BACKGROUND INFORMATION About COM Ports and IRQ's PC's have from one to four COM ports. These ports may or may not be attached to serial sockets on the back of the PC. COM ports are used to connect serial devices - such as a mouse, modem, PCMCIA socket, or another computer - to a PC. Each PC usually has one or two serial sockets on the back which are connected as a COM port. Often the 3rd (and 4th) COM port(s) are accessed from DOS through one of the slots on the motherboard. A user may install an additional serial port card that contains one or two additional ports and sockets and allows up to four external serial devices to be attached to a PC. Devices such as modems may be installed internally, but they still communicate via a COM port. In these cases, the PC may redirect, or manage, the COM port via a PC slot to the modem card. If the device uses a COM port which is normally associated with one of the external sockets on the back of the PC, that external port is taken away from the socket and given to the device. The implications of this will be clear in a moment. To complicate things further, each COM port gets the attention of the computer's processor by means of an Interrupt Request, called an IRQ. Think of these as "channels" by which the COM ports tell the processor that there is data waiting. There are only 8 IRQ's available to standard serial devices, and several are already dedicated internally. Because of this, COM ports 1 and 3 (if installed) share IRQ4, and COM ports 2 and 4 (if installed) share IRQ3. This usually means that if there is a serial device, such as the mouse, using COM1, and another device, such as a modem, using COM3, the two devices will experience an "IRQ conflict" which is likely to disable both. These conflicts must be resolved before communication can be made. How to Know the Port Configuration There is no substitute for having the hardware documentation for your PC or the services of a system administrator to analyze your PC and determine how the COM ports are configured. Often the vendor of the PC can advise on how the ports were set up before sale. Failing those things, experimentation is required. On Windows NT, you may run the program called Microsoft Diagnostics (MSD). At a DOS prompt, type WINMSD . From the screen that comes up you can learn many valuable facts: Whether you have a Bus-type mouse or a Serial-type mouse, which serial ports are installed, how many COM ports you have, what resources they are using, and if there are any IRQ conflicts. For Windows 95/98 users, right-click on My Computer, and choose Properties from the menu. Click on the Device Manager tab of the System Properties window. Click on the Ports (COM & LPT) to see what COM ports exist. This information is only as accurate as Windows Setup "sees", and may leave out certain devices, such as the IR port on a laptop. If you have a serial mouse on COM1, and you have an internal modem, you most likely have the modem configured on COM2. You may check this by launching one of the communications programs used with the modem and check its "setup" or "configuration" or "settings". The COM port in use will be indicated. If the number of devices in use match the number of COM port sockets on the back of the PC, there is no socket available for communications. What Can be Done? There are generally two causes for communication failures that prevent a successful HotSync operation: -no connection between the COM port and serial socket -hardware resource conflicts Some solutions for overcoming these issues are outlined below. No Connection Between COM Port and Serial Socket Some PC's, particularly laptops, may not have a COM port address assigned to the serial socket. See the previous section entitled "How to Know the Port Configuration" for directions on checking your system's Control Panel under Ports for COM port assignments. You may need to review your owner's manual or contact the manufacturer for more instructions. Alternatively, all other serial sockets may be in use on your system. In that case, you will need either to unplug another device using a serial socket or add a Serial Port Card. These are available from computer stores at prices from $10 to $50+. Give the COM port on this board a unique IRQ value (less than 16) if possible. You will have to use a diagnostic program like Microsoft Diagnostics or Norton Utilities to determine what IRQ's are available. (See the section entitled "How to Know the Port Configuration" for more detail.) Hardware Resource Conflicts A number of hardware devices (See the section entitled "About COM Ports and IRQ's") may prevent a successful connection. Some problems and their solutions are outlined below. Serial Ports in Use Unplug the external modem or mouse to make a port available. If you are using an external modem, it is very easy to unplug the modem and plug in the communications cable. Some users employ a switch box. The switch allows them to switch between multiple devices and the PC. Switchable PCMCIA Slots Many new laptop computers have one or two PCMCIA slots configured as COM2. On some systems, these can be switched off to allow the COM2 socket to be activated. Check the hardware documentation for your laptop for details. Unplug the Network Connection On systems which have a network connection attached to a COM port socket, you may be able to disable the network software and remove the connection in order to plug in the serial communications cable. Check with your system administrator. Change the IRQ and COM Port of the Modem Move your serial mouse to COM2 and your modem to COM3 (Consult your modem manual for instructions on reconfiguring!). You may then be able to use COM1 for your communications software IF your modem is not powered on while communications is in progress. Pentium Upgrade Note Some after-market Pentium processor upgrades leave the PC with only one COM port turned on. This is not true of new PC's which come with Pentium processors installed. If you determine that this is the case, you can go into the PC's setup and turn on the second COM port if the PC is so equipped. Follow the instructions included with your hardware on performing this adjustment. When in doubt, please consult your hardware documentation, PC vendor, or your Systems Administrator for additional information on configuring your communications ports. Note for Laptop Users Laptops are particularly susceptible to COM port configuration difficulties. Review your laptop's documentation carefully to determine what COM ports you have and what ports are available. If your laptop has an IR or infrared port, you may need to disable the infrared port before enabling the COM port that you wish to use. Some laptop owners have needed to lower the speed at which they perform a HotSync operation to connect consistently. COM port speeds may be modified via the Setup and Speed options in the HotSync menu on the Desktop. Also be aware that Advanced Battery Support programs have been known to interrupt HotSync operations. This problem is caused by the laptop turning off the serial port when it goes into standby or power-saving mode. To correct this, you can either configure the computer to leave serial ports on during standby mode (if possible: consult your computer's manual), turn off the power-saving features of the laptop, or always restart the HotSync Manager after the laptop wakes up from standby or sleep mode. Modifying COM Ports on IBM ThinkPads Please Note: The information provided below is made available for the convenience of our users with IBM ThinkPads. This information has been made available from IBM Technical Support and ThinkPad users. If you have any further questions beyond the scope of this HelpNote, please refer to your ThinkPad documentation and/or contact IBM Technical Support for further assistance. In order to use an IBM ThinkPad with your handheld, you may need to change the COM port settings on the ThinkPad before installing the Desktop and performing a HotSync operation. All ThinkPad users who have the "ThinkPad Features" program installed on their ThinkPad should follow the steps below: 1. Go into Start|Programs|ThinkPad|ThinkPad Features. 2. Disable the IR (infrared) Port. 3. Enable Serial Port on COM 1. 4. Restart the machine. 5. Install the Palm Desktop. Version 8/19/98 Palm Computing, a 3Com Company