Cermetek Microelectronics, Inc.
CH1817 Family of Low Profile DAA Modules
Table 1.
CH1817 Family Pin Description.
Pin
Name
I/O
Function
1
TIP
I/O
TIP. Direct telephone line connection.
2
RING
I/O
RING. Direct telephone line connection.
3
OFFHK
I
OFF HOOK. When set LOW, the CH1817 is placed On-Hook. When set HIGH, the
CH1817 is placed Off-Hook to answer or place a call. This input can also be used
for pulse dialing. NOTE: When answering incoming calls in response to a ring
indication on RI, internal relay contact degradation may occur if OFFHK is set HIGH
before RI returns to its HIGH state.
4
RI
O
RING INDICATION. It is asserted LOW by the CH1817 during the 2 second ON
portion of the incoming AC Ring Signal and is asserted HIGH during the 4 second
idle period between rings. An envelope of the AC ring signal may be created using
the application circuit shown in Figure 2.
5
RCV
O
RECEIVE. This provides the signal or audio output with respect to ground and must
be AC coupled with a 0.1
µF capacitor to eliminate DC offset.
6
XMIT(-)
or
N/C
I
or
-
TRANSMIT SIGNAL (-). Input a differential AC coupled audio signal with respect to
XMIT(+), CH1817-D versions only. All others, No Connection. For single ended
operation of CH1817-D, connect this pin to ground through a 0.1
µF capacitor.
7
VCC
I
POWER SUPPLY. +5V ± 5%
8
XMIT(+)
I
TRANSMIT SIGNAL (+). Input an AC coupled audio signal with respect to ground.
Input a differential signal with respect to XMIT(-) for the CH1817-D versions only.
9
GND
I
Ground. Must be connected to signal ground. Note: Noise should be less than
25mV peak-to-peak.
2002 Cermetek Microelectronics, Inc.
Page 3
Document No. 607-0007 Revision B (01/02)
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