Patton electronic 1082/F - Manual (Page 9)

9
The first G.703 interface is in Network Timed mode. The second is in
Recover Clock mode. See Figure 2.
Figure 2. Network Loop Extension Configuration
Timing of Application 2: Network Replacement. The first modem uses
an internal timing source and supplies the timing for the entire system. The
first G.703 recovers the timing and clocks the data into the FIFO. The Tx of
the first modem takes its internal clock and sends it (TXCLK1) to the
G.703 FIFO for data (TXD1). The Rx of the second modem recovers the
clock and presents a “jittery” clock and data to the second G.703’s trans-
mitter. It has to smooth the clock before it uses the clock to transmit.
The Rx of the second G.703 recovers the timing and clocks the data into a
FIFO. The Tx of the second modem sends the second modem’s recovered
clock (TXCLK1) to the G.703 FIFO for data (TXD1). The Rx of the first
modem uses its internal clock (RXCLK1) to send data (RXD1) into the
FIFO. The Tx of the first G.703 smoothes the first modem’s recovered tim-
ing and sends it to the FIFO for data.
RX
TX
CSU
DTE
G.703
RX
RX
RX RX
RX
2 or 4 Wire
TX
G.703 INTF-
MODEM
TIMED MODE
SECOND MODEM
FIFO TX
SMOOTHED
TX
TX
TX FIFO
FIFO
G.703
FIFO
HOST
MODEM -
RECOVERED
TIMING
FIRST MODEM
HOST MODEM
INTERFACE
(EXTERNAL)
TIMING
G.703 INTERFACE
NETWORK
TIMED MODE
NETWORK
G.703 TX
SMOOTHS
RX MODEM
CLOCK