ch1786nh ETC-unknow, ch1786nh Datasheet - Page 13

• Manufacturer Part Number: ch1786nh
• Description: Ch1786 Family Ultra Small 2400bps Modems
• Manufacturer: ETC-unknow

Cermetek Microelectronics, Inc.
1. Currently Limiting PSTN Protection Line
2. Over Voltage and Lightning Protection.
2003 Cermetek Microelectronics, Inc.
Figure 7.
Device.
Currently limiting devices are mandatory to meet
UL safety standards. To maintain conveyed FCC
Part 68 approval, the current limiting components
identified as F1 and F2 in dashed Box #1 must
also survive FCC Part 68 surge testing. Refer to
Cermetek Application Note #126, Supplemental
PSTN Line Protection, for more details. Refer to
Application Note # 130, Summary of Recommend
Suppliers, for a list of suppliers and associated
part numbers.
A. A Polyfuse (rated at 0.15 amps) is preferred
B. Resistors (10Ω carbon film or 1/8 watt
C. Although CSA CS-03 Part 1 (Canada) follows
A. Surge Protection is provided by internal
because it resets automatically upon removal
of the current flow.
are also acceptable. Refer to Application Note
#130 for a complete list of recommended
vendors and associated part numbers.
minimum) may be used in Canada, as Canada
has no requirements that PSTN equipment be
operational after a Type B surge test.
the requirements of FCC Part 68 (USA),
Cermetek
(Canada) and/or a certified independent lab to
verify compliance.
10Ω resistors (carbon film or SMD parts 1/8
watt minimum) as described in paragraph B
above.
circuitry contained within all CH1786 Products
except the CH1786NH (see Figure 7).
additional external components are required to
maintain conveyed FCC Part 68 approval for
all
CH1786NH).
CH1786
PSTN Line Interface for all CH1786 Products.
recommends
Products
For Canada, use either
Non-resettable devices
contacting
(excluding
DOT
the
No
Page 13
3. EMI/RFI Suppression.
B. For CH1786NH, the required surge protection
C. In most environments, 2 terminal surge
No external EMI/RFI noise suppression circuitry is
required to maintain conveyed FCC Part 68
approval.
required for other reasons, may be added as
described below in Sections 3A-3B without
adversely affecting FCC Part 68 approval.
A. To provide adequate EMI/RFI suppression,
B. Capacitors C1 and C2 should not exceed
(identified as D1 in dashed Box 2) must be
supplied externally.
include some form of surge protection as
described herein to maintain conveyed FCC
Part 68 approval.
suppressors are adequate.
environments, use an external 3 terminal
device with an earth ground.
the capacitor/inductor network contained in
dashed Box #3 should be located as close to
the RJ11 Jack as possible.
network should be provided with an excellent
ground path to the chassis.
0.005µf. They must have a rating of 1.5KV
and typically are 0.001µf ± 20%. Inductors L1
and L2 may be either individual inductors or a
dual inductor. Refer to Application Note #130
for a complete list of recommended vendors
and associated part numbers.
applications, choose capacitors and inductors
that are UL 1950 listed. The actual values of
the components used may vary depending on
the end product design.
CH1786 Family of Ultra Small 2400bps Modems
However, additional suppression, if
Document No. 607-0004 Revision L1 (06/03)
The purchaser must
Further, this
For severe
For UL