Black Box ME621A Manual page 13

MODULAR FIBER CAMPUS DRIVER, MFCD PLUS
Because communication between two Model ME620As is always
synchronous, you must set these switches whether your application is
async or sync. For X.21 or async applications, configure one unit for
internal clock mode and the other for receive recover clock mode.
S S1-7: DTE C
WITCH
The setting for Switch S1-7 determines whether DTE control of remote digital
loopback test is enabled or disabled. If DTE control is disabled, the DL test can
only be initiated by the front-panel switch. If DTE control is not available, set
switch S1-7 to the Off position.
S1-7
On
Off
S S1-8: DTE C
WITCH
The setting for switch S1-8 determines whether DTE control of local analog
loopback test is enabled or disabled. If DTE control is disabled, the LAL test can
only be initiated by the front-panel switch. If DTE control is not available, set
switch S1-8 to the Off position.
S1-7
On
Off
12
DL
ONTROL OF
Setting
Enabled
Disabled
LAL
ONTROL OF
Setting
Enabled
Disabled
NOTE
Description
Respond to DL requests from DTE
Ignore DL requests from the DTE
Description
Respond to LAL requests from DTE
Ignore LAL requests from the DTE