Motorola 880, Service Manual

Page: 9 / 171

© 1997 Motorola, Inc. 68P09403A50 1
DESCRIPTION
Dual Band 880/890 (DCS/GSM) Cellular Subscriber Sector
Description
Product Description
General
This phone is a microprocessor controlled,
full duplex, synthesized FM radiotelephone
using digital modulation techniques, for use
in compatible 900 MHz/1800 MHz cellular
radiotelephone systems. When operated
properly, the equipment will provide the
user with land-linked telephone service
through individual cell site base stations, all
linked to a central control office. The phone
has a 3.0 Watt maximum power capability.
Physical Packaging
The transceiver circuitry is contained in a
water resistant polycarbonate plastic
housing measuring (including Slim battery
pack) 138 mm (L) x 59 mm (W) x 27 mm (D).
It weighs approximately 215g; includes
Super Slim LiIon battery pack and antenna.
The main internal electronic circuitry is
contained on two multi-layer boards. The
keypad board assembly incorporates the
display, keypad contacts and mylar
switches, alert transducer, vibrator and
earpiece speaker. The display is glued to the
board by a foam gasket with electrical
connections via a short flex strip. Also on the
keypad board are the 6 pin contacts for the
SIM card, the mute and volume button
contacts and magnetic reed switch.
The RF/Logic board consists of the Audio/
Logic circuitry on both sides of the lower
half of the board and the RF circuitry on the
top half. Electrical connections between the
two sides of the board are provided by feed-
through connectors at various points on the
board. Also on the main board are the acces-
sory connector, the battery contacts and the
microphone plug socket. The microphone
sits in a small pocket in the keypad
membrane itself and connects to the main
board via two wires terminated in a plug.
The accessory connector, situated at the base
of the phone on the main board, allows
connections to the audio/logic circuitry and
antenna for accessory applications such as a
mobile adaptor and chargers. When the
accessory RF connector is used the RF to the
top antenna is disconnected. Grounding
shields, (with removable covers) on the
main board provide electrical isolation and
protection to the RF circuits. Interconnection
between the two main boards takes place via
a 41 pin female connector situated on the
display board, and a corresponding male
connector on the main board.
Operating power for the personal telephone
can be obtained from anyone of the
following sources:
• -Slim Battery Lithium (SNN4383)
This rechargeable Lithium Ion battery
pack is the lightest Motorola battery
offered for the phone. It measures 9.4mm
thick, and gives approximately 58-75
hours standby.