Cermetek Microelectronics, Inc.
High Speed Internet Modem Family
2005 Cermetek Microelectronics, Inc.
Page 11
Document No. 607-0017 Revision I1 (05/05)
Pins 1 and 2 function as both input and output
connections to the PSTN. To maximize field reliability
in hostile environments, to ensure UL compliance, and
also optionally for FCC part 15 compliance, these two
pins may be routed through an external network such
as that briefly described in figure 3 or as described in
more detail in Cermetek Application Note # 126,
Supplemental PSTN Line Protection.
PHONE LINE CONNECTION GUIDELINES
1. The iModem must be mounted in the final
assembly such that it is isolated from exposure to
any hazardous voltages within the assembly.
Adequate separation and restraint of cables and
cords must be provided.
The circuitry from the iModem to the telephone
interface must be provided in wiring that carries
no other circuitry other than that specifically
allowedin the FCC rules (such as A and A1
leads).
2. Connection to the PSTN line should be made
through an RJ-11C jack.
3. PCB traces from the iModem’s RING and TIP
pins to the RJ-11C jack must be 0.1 inch spacing
or greater to one another and 0.2 inch spacing or
greater to all other traces. The traces should
have a nominal width of 0.020 inches or greater.
4. The RING and TIP PCB traces should be as
short as possible and oriented to prevent
coupling with other high speed or high frequency
signals present on the host circuit PCB.
5. No additional circuitry other than that shown in
Figure 3 may be connected between the iModem
module and the RJ-11C jack. Doing so will
invalidate the conveyed FCC approval.
6. The iModem, the RJ-11C jack, the interfacing
circuitry and all PCB traces must be contained on
a PCB with a 94 V-0 flammability rating.
7. The supplied FCC registration label must be
applied visibly on the outside of the product.
8. The product’s User Manual must provide the user
with instructions for connection and use as
recommended in the FCC Registration Section
below.
CANADIAN APPROVALS
The iModem family is approvable for use by DOT to
Industry Canada CS-03 Part I. However, per
Canadian procedures, approval can only be granted
after the iModem has been installed into the end
product. Typically, Canadian approval is obtained by
submitting the final end product to an independent test
house or consultant for evaluation. The test
house/consultant then forwards the test results and
applicable documents to the regulatory agency.
Cermetek offers a list of consultants to assist with this
process.
iMODEM HANDLING AND ASSEMBLY
RECOMMENDATIONS
The iModem contains static-sensitive components and
should only be handled by personnel and in areas that
are properly protected against static discharge.
There are two mounting techniques that are
recommended for physically connecting the iModem to
a PCB:
1. Direct
soldering.
2. Sockets.
Direct Soldering.
The iModem may be wave
soldered onto a circuit card. All iModem products are
sealed and will not be harmed by industry standard
wave soldering processes.
Socketing.
The socket approach to mounting
eliminates cleaning and desoldering concerns. When
the socket is used, it must make a solid connection to
all pins. Failure to do so will cause unreliable or
intermittent operation. Also, steps should be taken to
assure that the module remains tightly seated in the
socket after the end product is shipped. Cermetek
recommends the 50 pin strip socket CES-150-01-T-S
by Samtec. Refer to Application Note# 130, Summary
of Recommend Supplies, for a list of supplies and
associated contact information.
FCC REGISTRATION
All CH21XX iModem products are registered with the
FCC under Part 68. To maintain the validity of the
registration, notice of the restrictions the FCC places
on the iModem and its use must be served to the end
user of the product containing the iModem.
In addition to restriction notification, the FCC requires
that Cermetek make all repairs to all products in the
iModem family. If repairs are necessary after
installation of the iModem and the end product has
been delivered to the end user, the end product must
be returned to the end product supplier where the
iModem can be removed and then forwarded to
Cermetek for repair. The following notice is
recommended and should be included in the end
product’s user manual.
