Lucent Technologies LT7901 Mobile Phone Teardown

Main Features

Low-end PHS (Personal Handyphone System) clamshell form mobile phone. Small 1.4 CSTN 4K color display (102 x 80) with no secondary (external) display, no camera, no frills!

Lucent Technologies LT7901 Mobile Phone Main Image

Without evidence to the contrary, this PHS system phone appears to be built by in China for consumption within China. The only information available found on this phone is all China domestic in nature. PHS is a local area wireless technology, or cordless technology.

PHS originated in Japan and in the mid 1990s was used extensively in local cities. When cellular communications became ubiquitous, the need for PHS diminished. Japan has seen decreasing PHS subscribers since the late 1990s.

China is following in Japan's shoes. China's fixed line carriers are offering PHS for village to village communications. For rural villages that do not yet have cellular infrastructure, or for those villagers that cannot afford mobile handsets, PHS is a cost effective solution. PHS subscribers will continue to increase through 2008, but as cellular technologies proliferate through China and costs come down, PHS will decline in China as it did in Japan.

UTStarcom is the market leader for PHS equipment, including handsets. UTStarcom partners with Sanyo of Japan to manufacture PHS handsets. Other Chinese manufacturers use module solutions, and Kyocera is the main supplier here. The major chipset providers are Japanese semiconductor manufacturers including Asahi, Mitsubishi, Oki, Toshiba, NEC, Rohm, and Seiko Epson.

Lucent Technologies LT7901 Mobile Phone Cost Analysis

In PHS, where the name of the game is inexpensive access, it also makes sense that phones built to access the network would be made inexpensively, and the Lucent LT7901 is one of the least expensive handsets we have analyzed to date. Even when compared with our recent analysis of several domestic brand low-end GSM phones from Konka, Bird and TCL, this Lucent phone sets a new low in our history of phone analyses.

Primarily this low cost is driven by simple design, and lack of features, however, lower cost RF/PA and other components also contribute to this factor along with the recent drop in LCD prices. Furthermore, all of the lowest cost handsets we have analyzed have been, logically, produced in China where labor rates are unparalleled, and typically add little to the cost.

Lucent Technologies LT7901 Mobile Phone - PHS RF Module - Functional Areas

Display (1.4 Inch, CSTN 102x80 4K Color - No secondary)

Kyocera Baseband & Pwr Mgmt Chips

Memory (MCP - Flash 32Mbit NOR, 4Mbit SRAM)

Various Colored LEDs

RF Transceiver & PA

Rigid PCBs

Battery

Materials and Manufacturing*/**

* - The total materials and manufacturing costs reported in this analysis reflect only the direct materials cost (from component vendors and assorted EMS providers), manufacturing and test. Not included in this analysis are costs above and beyond the manufacture of the core device itself - cost of packaging, literature, accessories, shipping, logistics marketing and other channel costs including not only EMS provider and Lucent's margin, but that of other resellers. Our cost analysis is meant to focus on those costs incurred in the manufacture of the core device (the phone and battery in this case) itself.

** - The charger and box provided seemed unrelated to the Lucent phone and were not included in the photos or cost analysis.

Design

This is another phone design that we are seeing as increasingly popular in low end phones - the bulk of the processing, in fact the entire core of the phone itself resides on a stand-alone daughter board (referred to in our analysis as the PHS RF Module) which is attached to a rather lame Main printed circuit board which serves primarily as the interface and interconnect substrate for all of the internal and external interconnect, keypad contacts, etc.

Furthermore, this entire design appears to be a Kyocera reference design and employs a Kyocera digital and analog basebad chipset with other prominent Kyocera sub-components. This is the first phone we have encountered with this design.

PHS RF Module Main Components

Lucent Technologies LT7901 Mobile Phone - PHS RF Module

Lucent Technologies LT7901 Mobile Phone - PHS RF Module

• DBB - Kyocera - KBR42-010 - Digital Baseband Processor
• ABB - Kyocera ASIC (?) - Analog Baseband Processor / Power Management Chip

Memory

• NOR Flash / SRAM -Intel MCP - RD38F1010C0ZTL0 - 32Mbit NOR Flash and 4Mbit - This is about the lowest memory content we have seen in any phone.

RF/PA

• RF Transceiver - Panasonic - AN6591FJM
• PAM - NEC - μPC8218T5A

Display

• 1.4 Inch, CSTN, 102 x 80 Pixel - Manufacturer Unknown - Low end in current market context.

User Interface

• PCM Sound Generator - Rohm - BU8793KN - 16 Chord Polyphonic Tone Generator - Fairly low end (most seen provide 40 chord polyphony).