10
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL WITH V.35 OR X.21)
Switches S2-6 and S2-7: Clock Mode
Use Switches S2-6 and S2-7 to configure the HDSL Line Driver for internal,
external, or receive recover clock mode.
Table 3-2. Clock mode.
CO/CP
S2-6
S2-7
Clock Mode
Description
Unit
CO
On
On
Internal
Transmit clock
generated internally
CO
Off
On
External (DTE)
Transmit clock
derived from terminal
interface
CP
On
Off
Receive Transmit
clock
Recover
derived from the
received line
Off
Off
Reserved
Switch S2-8: Enable/Disable Loop Tests from DTE
Switch S2-8 may be used to allow the HDSL Line Driver to enter loopback
diagnostic tests (Local or Remote) when the V.35 DTE raises the appropriate loop
request pin (LLB: Pin L or RDL: Pin N). When Switch S2-8 is in the On position,
the HDSL Line Driver will enter local loopback or remote loopback at the request
of the DTE. When Switch S2-8 is in the Off position, the HDSL Line Driver ignores
DTE loop requests. In the Off position, loop requests may still be initiated by the
front-panel switch.
Table 3-3. Enable/disable loop tests.
S2-8
Setting
On
DTE Loopback Request Enabled
Off
DTE Loopback Request Disabled
