ADTRAN DSU IV ESP, User Manual

Page: 74 / 194

Chapter 7. Configuring DTE Options
7-8 DSU IV ESP User Manual 61204011L1-1
The
E
XTERNAL
C
LOCK
option is normally used in modem tail circuit
applications. A DSU Tail Circuit cable interconnect diagram for this
application is shown in Figure E-1 on page E-2 in Appendix E.
The
E
XTERNAL
C
LOCK
option is also recommended when the
EIA-232 connector is used for 56 kbps and 64 kbps applications.
Using this option eliminates data errors caused by excessive delays
in the DTE transmit clock receiver and transmit data driver.
The I
NVERT
C
LOCK
option is recommended when the EIA-232
connector is used for rates other than 56 kbps or 64 kbps.
Clear to Send (CS) Options
The C
S
O
PTIONS
menu is used to select the control mode for the CS
lead. The default factory setting is F
OLLOWS
RS
WITH
CS D
ELAY
S
HORT
.
If one of the options chosen involves R
EQUEST TO
S
END
(RS), then
the delay from RS to CS must be selected. Table 7-1 on page 7-3
shows the AT Commands used to set the CS options.
Specified times for the short and long delays at the different
operating speeds are shown in Table 7-3.
Table 7-3. Short & Long Delays at Different Operating Speeds
Rate Short Delay Long Delay
64
56
19.2
4.8
2.4
1.1 ms
1.1 ms
1.5 ms
1.5 ms
1.5 ms 16.1 ms
16.1 ms
16.5 ms
16.5 ms
16.5 ms