Chapter 1 – Product Description and Specification
8
Multi-Tech Systems, Inc. MultiModem CDMA User Guide
Cellular Information
Antenna System for Cellular Devices
The cellular performance is completely dependent on the implementation and antenna design. The integration of the antenna
system into the product is a critical part of the design process; therefore, it is essential to consider it early so the performance is
not compromised. If changes are made to the certified antenna system of the MultiModem, then recertification will be required
by specific network carriers such as Sprint. The Antenna System is defined as the UFL connection point from the MultiModem
to the specified cable specifications and specified antenna specifications.
PTCRB Requirements for the Antenna
There cannot be any alteration to the authorized antenna system. The antenna system must maintain the same specifications.
The antenna must be the same type, with similar in-band and out-of-band radiation patterns.
FCC Requirements for the Antenna
The antenna gain, including cable loss, for the radio you are incorporating into your product design must not exceed the
requirements at 850 MHz and 1900 MHz as specified by the FCC grant for mobile operations and fixed mounted operations as
defined in 2.1091 and 1.1307 of the FCC rules for satisfying RF exposure compliance. The antenna used for transmitting must
be installed to provide a separation distance of at least 20cm from all persons and must not transmit simultaneously with any
other antenna transmitters. User and installers must be provided with antenna installation instructions and transmitter operating
conditions to satisfying RF exposure compliance.
Antenna Specifications
CDMA RF Specifications
CDMA 800
CDMA 1900
Frequency RX
869 to 894 MHz
1930 to 1990 MHz
Frequency TX
824 to 849 MHz
1850 to 1910 MHz
CDMA Antenna Requirements/Specifications
Frequency Range
824 – 894 MHz / 1850 – 1990 MHz
Impedance
50 Ohms
VSWR
VSWR shall not exceed 2.0:1 at any point across the bands of operation
Typical Radiated Gain
3 dBi on azimuth plane
Radiation
Omni-directional
Polarization
Vertical
Antenna Loss
Free space not to exceed -3dB
TRP/TIS
The total radiated power (TRP) at the antenna shall be no less than
+21/20 dBm for PCS/Cell channels respectively, and the total isotropic
sensitivity (TIS) at the antenna shall be no less than -104/104 dBm for
PCS/Cell channels respectively.
RS232 15-Pin Connector
The following table explains the pin functions.
PIN
EIA
CCIT
Designation
RS-232
1
DCD
109
Data Carrier Direct
6
RX
104
Receive Data (out)
2
TX
103
Transmit Data
8
DTR
108.2
Data Terminal Ready
9
GND
Signal Ground
7
DSR
107
Data Set Ready
12
RTS
105
Request to Send
11
CTS
106
Clear to Send
13
RI
125
Ring Indicator
Reset
14
RESET
To reset, connect to GND momentarily
(typical: 20mSec). Open for normal
operation.
