ch1817lm ETC-unknow, ch1817lm Datasheet - Page 2

• Manufacturer Part Number: ch1817lm
• Description: Family Of Low Profile Daa Modules
• Manufacturer: ETC-unknow

¤2002 Cermetek Microelectronics, Inc.
Cermetek Microelectronics, Inc.
Hook Switch. The OFFHK input is used to control the
on-hook and off-hook status of the CH1817. When
OFFHK is low, the CH1817 is in the On-Hook State.
This indicates to the CO that the CH1817 is ready to
receive calls.
allows the CO supplied loop current to flow, indicating
either it is answering a call or preparing to place a call.
2-Wire To 4-Wire Hybrid Converter. This block has
two functions:
1. It applies the XMIT signal to the phone line.
2. It subtracts the desired signal from the total
The accuracy of this derivation depends on how
closely the impedance of the phone line matches 600
Ohms. Generally, a small amount of the XMIT signal
will appear at RCV. The ratio of the applied XMIT
signal to the received XMIT signal is called Trans-
Hybrid Rejection, or Trans-Hybrid Loss. On a 600:
phone line, the CH1817 DAAs have very high trans-
hybrid rejection, typically 23 dB.
Figure 2. Typical CH1817 Application.
The FCC requires that the DTMF tone not exceed
0dBm.
Attenuation
Input Impedance
outgoing signal on the phone line to derive the
RCV signal.
Input: Active High
Active Current: 4mA
When OFFHK is high, the CH1817
OFFHK
CH1817-D
0dBm
150K:
NOTE
9.5dBm
150K:
CH1817-L
XMIT
Page 2
TRANSMIT SIGNAL
The outgoing analog signal to be transmitted through
the phone line should be applied to the XMIT pin (with
respect to GND) and must be AC coupled as shown in
Figure 2. For the CH1817-D a XMIT (+) and XMIT (-)
pins provide a differential input.
attenuates the transmit signal by 9.5dB, 0dB for the –D
option. Therefore, a transmit signal of 0dBm for the –L
option (-9.5 dB for –D) applied to XMIT will comply
with the FCC Part 68 requirement for data signals of –
9dBm across TIP and RING.
RECEIVE SIGNAL
The incoming analog signal appearing between TIP
and RING is presented at RCV with respect to GND
and must be AC coupled to the user equipment
receive input. The CH1817 does not gain the receive
signal.
strength of –9dBm to below –50dBm.
Gain: 0dB
Out impedance: 100:
Typical Output Signal:
Signal referenced to GND
AC coupling required
CH1817-DM
6.5dBm
150K:
Receive signals can vary from a maximum
CH1817 Family of Low Profile DAA Modules
Document No. 607-0007 Revision B (01/02)
RCV
-9dBm to –50dBm
2.5Vrms to 0.27mVrms
CH1817-LM
6.5dBm
150K:
The CH1817-L