9
V.35 FOLD
3.3 Transmit Data Clock
Data timing is synchronized among
all connected devices in one of three
ways:
• Internal Clock (factory setting)
• Recovered Clock
• External Clock
DIP switch S3 controls the selection
of the clock timing. See Table 2 for
DIP switch settings. The fourth
switch position on DIP switch S3 is
unused. Figure 2 shows where the
DIP switch is located on the ciruit
board.
I
NTERNAL
C
LOCK
The FOLD generates Transmit Data
clock and presents clock to the
attached DTE on TCA and TCB. The
DTE then presents synchronized
data to the FOLD on pins TDA and
TDB.
R
ECOVERED
C
LOCK
The Transmit data clock presented
to the DTE is synchronized with the
timing of data received from the
remote device.
E
XTERNAL
C
LOCK
The local DTE determines clocking.
The clock is presented to the FOLD
on Pins ETCA and ETCB, and
returned as TCA and TCB.
M
ASTER
C
LOCK
To create a master clock, one of the
FOLDs should be set to internal or
external clocking and the other
FOLD set to recovered clock.
3.4 Carrier—Constant/Switched
Jumper W2 is used to select Constant
Carrier or Switched Mode. See
Figure 2 for the jumper’s location on
the printed circuit board. This
option determines how the FOLD
reacts to an RTS signal from the
local V.35 device. The FOLD is
defaulted to Contant Carrier Mode.
C
ONSTANT
C
ARRIER
M
ODE
Place jumper W2 over position E.
The FOLD functions as if the
attached V.35 device is constantly
asserting RTS:
• The fiberoptic transmitter is
always on, and the FOLD’s CTS
signal remains high. Any data
sent by the attached V.35 device
is automatically transmitted by
the FOLD.
• The RTS indicator on the
FOLD’s front panel will always
be on, regardless of the data
activity on the V.35 interface.
The CD indicator on the remote
FOLD will remain lit.
Table 2. Clock Settings
Data Clock
Switch
1
2
3
4
Recovered
On
Off
Off
On
Internal
Off
On
Off
On
External
Off
Off
On
On