MagTek OMTD 99875144 - Manual (Page 15)

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SECTION 3. IMPLEMENTATION NOTES
The following sections define specifics of the OMTD implementation of the OPOS controls.
SINGLE SERVICE OBJECT
The OMTD product implements a slight deviation from the OPOS Specification. The OPOS
Specification specifies that there is a separate control object for each device class and separate
service object for each device model. OMTD conforms to the idea of a separate control object
per device class, but it diverges from the specification in that OMTD contains a single service
object that is used for all device models.
The reasoning behind the separate service object idea is that each device has its own interface
(i.e., set of commands) and communication channel (e.g., RS-232 or keyboard) which requires
different implementations of the OPOS functionality.
The OMTD product contains only one service object, the common service object, because the
MTD driver handles the data medium and the transport protocol to the device, providing uniform
access to the device regardless of the type of connection and device model.
POTENTIAL PROBLEMS IN WINDOWS 95/98
The MTD property sheet (settings) in Windows 95/98 has an additional check box that is used to
enable or disable OMTD for that device. When a new device is installed, the box is checked by
default if OMTD is installed.
When the box is checked, the class installer creates and maintains a registry entry that maps the
device name to the SO for each device class supported by the device. The registry entry is made
up of the friendly name for the device (e.g., "micr+") and the device class (e.g., msr) separated
by a period. An example is: "Micr+.msr".
When the state of the box is changed from checked to unchecked or the device is removed from
the system, the class installer removes the device’s registry entries for each supported device
class.
MODIFYING OMTD DEVICE CONFIGURATION
The OMTD Service Object accepts per-device parameterization from the registry under the
following path:
HKLM\Software\OLEForRetail\ServiceInfo\MagTek\Devices\<device friendly name>
The following value is currently supported for each device: