Mitel SX-200 Practices page 1170

Peripheral Devices
Timing Modes
15.6 There are four modes of timing available with a DATASET 2100 series that are used
according to the current mode of operation.
Internal
- The Internal clock is used when the DATASET 2100 Series is operating in
Data Communication Equipment (DCE) mode. The transmit clock (SCT) to the Data
Terminal Equipment (DTE) is generated within the dataset's baud rate generator and
is not synchronized with PABX timing. The dataset's receive clock (SCR) to the DTE
is extracted from the data received from the far end dataset by the Phase Locked Loop
(PLL) circuit within the dataset.
;
'System
-The System clock is used when the DATASET 2100 Series is operating in
Data Communication Equipment (DCE) mode. The dataset's transmit clock (SCT) and
receive clock (SCR) to the DTE are extracted from the data received from the far end
devices by the Phase Locked Loop (PLL) circuit within the dataset.
Transmit External
- The DATASET 2100 Series uses the Transmit External clock in
either DTE or DCE mode; it is received from an external clock signal from the attached
device. From a DTE device, the clock is received on KS-232 pin 24; from a DCE device,
the clock is derived from the DCE device's SCR. The dataset's receive clock (SCR) to
the DTE is extracted from the data received from the far end device by the Phase
Locked Loop (PLL) circuit within the dataset.
Transmit and Receive External
- When the DATASET 2100 Series is operating in
DTE mode, the Transmit and Receive External clocks are derived from the attached
DCE device, The external transmit clock is received from the modem's SCR (pin 17)
and transferred to pin 24 by the DCE adapter; the external receive clock is received
from the modem's SCT (pin 15) and transferred to pin 18 by the DCE adapter.
Modem Adapter
15.7 DATASET 2100 Series are DCE devices, as are modems. To connect a DATASET
2100 Series to a modem requires that a Modem Adapter (pn 9141-I 00-l OGNA) be
connected to the R!S-232 connector on the data set. The Modem Adapter makes the
s DATASET 2100 Series appear as a DTE device to the modem. This is used primarily
in Modem Pooling applications.
DATASET 2100 Switch Settings
15.8 There is an 8-position DIP switch on the back of a Rack Mounted DATASET 2102
and a Standalone DATASET 2103. It is read once immediately after DNIC Sync is
achieved and the operating parameters are set according to the settings, ass defined
in Table 15-I. When viewed from the rear the DIP switches are labelled as follows:
12345678
User accessible switches
126 15-4
Revision 0 9109-096-12SNA
Issue1