Two Tables - Use 2 Criteria To Look Up Value

There are two tables:

Table 1

- UnitID
- StartDateTime
- EndDateTime
- CallNumber

Table 2

- VehicleID
- DateTimeStamp

What we need is to run a query that will return the following fields

- VehicleID
- DateTimeStamp
- CallNumber

Where:

- UnitID and VehicleID are equal
- DateTimeStamp from Table 2 is greater than the Start time in Table 1 and less than the End time in Table 1.

So without a relationship between the two tables how do we proceed?