ing, data is represented normally. With NRZI encoding, a logical one is represented by no transition and a zero is represented by a transition at the beginning of the bit. Most synchronous devices can be configured for either NRZ or NRZI. If a synchronous device is not configurable, it most likely is set to NRZ. Refer to the device’s user documentation for the encoding method.

The CRC Preset option allows the user to specify whether the polyno- mial used to calculate the CRC for each frame is preset to all 1s or all 0s. This option must match the synchronous device’s CRC-preset setting. The default is All 1s.

The Inter-frame Timer option can be changed to make the MultiFRAD wait a specified length of time between frames being transmitted on the data port. The user can choose delay times of 2,5,10 and 15 millisec- onds. A typical use for this parameter is to simulate transmission delays encountered with equipment that toggles hardware signals after transmission of each frame, like PC cards used to connect to legacy systems. The following options can be specified for the timer: Off, 2mS, 5mS, 10mS, and 15mS. The default is off.

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Multi-Tech Systems FR111 owner manual