KS16112/4
9600/14400 bps FAX MODEM
-
6
-
18
28
20
11
12
O
O
O
I
O
Clear to send
CTS is used to indicate of that the training sequence transmission
has been completed and the modem is ready to transmit any
data present at either the TXDI input pin in serial mode
( PDME bit is reset ) or in DBFR in parallel mode ( PDME bit is set ).
CTS
RLSD
DCLK
XTALI
XTALO
Received line signal detector
RLSD becomes active at the end of the reception of the training
sequence indicating the beginning of data reception.
If no training is detected but the received energy level is above
the RLSD off - to - on threshold, RLSD will become active.
Data clock
DCLK acts as received data clock or transmit data clock depending
on the state of the modem ( transmit or receive mode ).
The frequency of the clock corresponds to the data rate of the
selected modem configuration and is accurate to
±
0.01%.
In receive mode the RXDO pin is clocked out by
the modem on the rising edge of DCLK. In transmit mode, TXDI is
clocked in by the modem on the falling edge of DCLK.
Pin No.
Symbol
Type
Description
Oscillator In / Out
An external 24.00014 MHz ( KS16112 ) or 38.00053 MHz ( KS16114 )
crystal and two capacitors are connected to the XTALI and XTALO.
Alternatively, an external crystal oscillator of the appropriate frequency
can be connected to the XTALI input leaving XTALO unconnected.
In order to minimize electromagnetic emissions and ensure proper
oscillator start up and operation, the crystal and the capacitors should
be placed as close as possible to the XTALI and XTALO pins.
Further, the circuit board traces connecting the crystal and capacitors
to XTALI and XTALO should be as short as possible.
The use of circuit board vias should be avoided in the crystal
oscillator circuitry and circuit board traces should be routed using
curved turns.
PIN DESCRIPTION
( Continued )