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Situation:
When you connect to a host computer, you see a black screen with a blinking cursor, a black screen with random ASCII characters, or a toolbar with no host desktop icons.

Solution:
Sometimes, deleting temporary files and restarting the computer solves this problem, so this is the first thing to try. If that does not solve the problem, find the section below that describes the symptoms and follow the instructions. Click an icon to either expand ( ) or collapse ( ) each section. (If you cannot expand a section, then read the document Cannot expand or collapse a solution in a Symantec Knowledge Base document.)

Delete temporary files and restart the computer


Black screens are caused by two general categories of problems: connection problems and video driver problems. If you have tried deleting temporary files and that did not solve the problem, find the section below that describes the symptom, and follow the instructions:

Black screen with pcAnywhere toolbar


Black screen with blinking cursor
The symptom is a terminal window with a flashing white cursor in the upper left corner. The most common causes are listed below. Try one, and if it does not solve the problem, try a second one, and so on.

Remote connecting to a waiting remote
If you have launched a remote control item, and the other computer has a remote item waiting for a connection, you will see a black screen with a blinking cursor, and no connection is made. Make sure that either the other computer has a host waiting for a connection, or use a host item to connect to the waiting remote.

Modem drivers
Under Windows 9x/Me or Windows NT 4.0, modems operate through a setup file. This file is selected during installation and may come from the manufacturer (on disk or CD) or from Windows. If the selected file is incorrect, improper, or too generic, the modem may not work correctly with pcAnywhere and the black screen can result.

In addition, many modern modems are "software modems." WinModems and PCI modems fall into this category (see the document HCF and HSP modems and pcAnywhere). They operate by using software drivers to emulate functionality that is traditionally done by chipsets on the modem. If these drivers do not emulate correctly, the black screen with pcAnywhere can result.

Modem chipsets also contain basic operating instructions (called firmware). On occasion, the firmware for a new model or series of modems may be defective and can result in the black screen with pcAnywhere.

For any of these three potential problem areas, always go to the manufacturer's support web page for the latest issue of drivers. Reinstalling the modem with these newest drivers will very often resolve black screen problems with pcAnywhere.

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Note: If Windows is unable to locate a driver it can match with your modem, it will install it as a "Standard modem." This definition can limit some of the functionality of the modem and has been known to keep a modem from working correctly with pcAnywhere. For more information, please see the document "Standard Modem" and pcAnywhere.

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Modem speed
Most 28,800 bps and higher modems are rated to handle 115,200 bps data throughput. However, this speed can impose a burden on even the fastest CPU, causing data loss, data corruption, and slowed or lost connections. With pcAnywhere, it can also manifest as the black screen. Dropping the maximum speed to 57,600 bps, or even 38,400 bps, will often eliminate this problem. You may have to make this change to the remote modem or to the host modem, or to both. To determine the appropriate speed setting for your modem, please see the document How to determine the optimal settings for your modem.

To change the maximum speed for the connection:

1. Right-click the connection item you use for the connection (host or remote), and click Properties.
2. On the Connection Info tab, click Details. The Modem Properties window appears.
3. Click the next lower speed from the Maximum speed drop-down list.
4. Click OK, and then click OK again.

Third-party software answering incoming call
If the host computer is running another communications application along with pcAnywhere, the other application may answer the incoming call and the black screen can result. This most commonly happens calling into a Windows NT host that is also running the Remote Access Server (RAS). RAS will always answer the incoming call.

If you suspect a third-party application, shut down that application at the host and try your pcAnywhere connection again. If that application is RAS and the host cannot shut it off, you can make a dial-up connection to that server and make your pcAnywhere connection with an appropriate network protocol.

Telephone line problems
Line noise, nonstandard line voltages, or other devices sharing the telephone line with the modem can also cause the black screen. Other devices can include fax machines, and other modems or computers. Nonstandard line voltages are a common phenomenon in office environments where phone calls are routed through a PBX or some other type of switching device. PCMCIA (card) modems are often sensitive to this.

To eliminate the possibility of a phone line issue, make sure there are no other devices on the same line, and that you are connected to a direct line, not an office phone system. If you are still not sure, the local phone company should be able to test the line for voltage and interference.

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Note: Most phone companies will only test a phone line for reliability up to 9600 bps, and some will do no line testing at all.

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Interrupt request or COM port conflicts
If one of the modems is an internal, non-plug-n-play modem, then you may have an interrupt or address conflict with another hardware device. Standard configuration on many computers is to have COM1 and COM3 share an IRQ, while COM2 and COM4 share an IRQ. Some terminal emulation programs (like Procomm and Windows Terminal) and some fax programs can tolerate IRQ sharing. However, pcAnywhere is a full-featured remote control program and is more sensitive to this condition.

For more information concerning COM port and IRQ conflicts, see the document Resolving IRQ/Com port conflicts.

Serial communications parameters
Serial (asynchronous) communications depend on four basic parameters: flow control, data bits, parity, and stop bits. In the earlier days of communication, these settings varied from location to location. Today, flow control defaults to hardware, and the remaining settings are uniformly set to 8 data bits, no parity, and 1 stop bit (often abbreviated "8,none,1").

If anyone has changed any of these settings on either side of the connection, a black screen can result (sometimes a flow control mismatch will get as far as a black screen with toolbar).

To check these parameters

1. Right-click the pcAnywhere connection item, and then click Properties.
2. On the Connection Info tab, click Details.
3. In the Modem Properties window, on the Connection tab, make sure that the settings for Data bits, Parity, and Stop bits are set to 8, None, and 1 respectively.
4. Click Advanced.
5. In the Advanced Connection Settings window, if Flow control is set to Software, change it to Hardware. If neither is set, you can leave the setting alone.
6. Also check the modulation on this screen. It should be set to Standard.
7. Click OK, and then click OK again.

Recreate the host and/or remote items
A corrupt host or remote item can cause the pcAnywhere connection to fail. Delete the existing item and recreate a new host or remote item in pcAnywhere.


Black screen with ASCII characters

Black screen, then immediate disconnection

 

Document ID: 199753082441
Last Modified: 01/05/2007
Date Created: 05/30/1997
Operating System(s): Windows 95, Windows 98, Windows 98SE, Windows NT 4.0, Windows 2000, Windows Me, Windows XP, Windows NT3.51
Product(s): pcAnywhere 10.0, pcAnywhere 10.5, pcAnywhere 9.0

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