That estimate, compiled by J. Gold Associates in Northboro, Mass., is meant to give IT shops an idea of the replacement costs they might face should a U.S. court shut down BlackBerry service as part of an ongoing patent dispute between RIM and NTP Inc.

Analyst Jack Gold, principal of the firm, called a shutdown 'unlikely' but noted that many enterprises are asking what their alternatives would be if a shutdown did occur. There are more than 4 million BlackBerry users worldwide.

Gold's estimated replacement costs are based on buying new devices to replace BlackBerry handhelds, a cost Gold estimated at $300 per worker.

The second-largest cost would be the loss of productivity that would occur during any transition, including an estimated four hours per user in server downtime, switch-over time and time not having the device.

The third major cost would be finding other wireless e-mail middleware, which Gold pegged at $75,000. That figure came from an average of substantially differing costs from vendors such as Good Technology Inc., Extended Systems, Intellisync Corp., Nokia Corp. and Microsoft Corp.