and then filters the data to provide a good representation of the original information.
GSM stands for Global System for Mobile Communication, and is similar to both CDMA and TDMA
protocols in that it also provides digital cellular service with multiple links (conversations) on the same
carrier frequency. Like both CDMA and TDMA, GSM uses its own unique method of transmitting
conversation wirelessly. GSM is based on the platform of TDMA, but a more robust method when
utilizing the timeslots allotted for the milliseconds of data needing to be transferred/received. GSM is
also unique in that it utilizes a ‘smart card’ called Subscriber Identity Module (SIM) allowing for easy
portability between different GSM handsets. GSM handsets are not identified like both CDMA and
TDMA handsets by using an Electronic Serial Number (ESN); instead it is uniquely identified by the
International Mobile Equipment Identity (IMEI).
The type of digital handset that will be installed into the vehicle will be contingent upon the local
carrier’s signal processing capabilities. Some carriers only use CDMA protocols whereas others may
only use TDMA or GSM. It is possible in some areas for the customer to have a choice of all three
protocols to use when carriers in the same cellular coverage area offer CDMA technology while others
offer TDMA or GSM technologies. Some carriers are requiring special ‘un-lock codes’ for handsets that
are to be used in their coverage area and on their systems. It is important to be aware of this in the event
that you experience trouble with activating the phone. More information regarding these codes is
available through the carrier, which the handset is being activated on. Refer to the Mercedes-
Benz/Motorola website (www.mbconnectedcar.com) or Motorola’s Customer Support at 877-668-8600
for carrier contact numbers.
1.2.2 CDMA, TDMA and GSM Handset Descriptions
The CDMA StarTAC and Timeport handsets have three partially blue keys with an icon that represents a
"soft key" function. Soft keys are keys that change their function according to what is being displayed
on the screen for a particular function. These keys are located on the fifth row of the keypad and are on
the "RCL", "STO", and "CLR" keys.
Another way to differentiate between a TDMA and CDMA handset is to compare the displays. The
CDMA handset uses the OELD (Organic Electro Luminescent Display, Timeport only). The TDMA
handset uses 5-line LCD dot-matrix display. The TDMA Timeport and v.60t handsets have a fixed
antenna compared to the traditional extendable antenna on both of the StarTAC’s and CDMA Timeport
and v.60c. The CDMA phones and TDMA v.60t indicates that the user is in digital mode by displaying a
“D” inside a square border on the left side of the display, vs. a "D" with no border in the lower left hand
corner of the TDMA StarTAC and Timeport handsets. When in analog mode, the StarTAC and
Timeport CDMA handsets display an “A” inside a circle; the StarTAC and Timeport TDMA handsets
are in analog mode when no “D” is present in the lower left corner of the display. When both the CDMA
v.60c and TDMA v.60t are in analog mode an “A” is present inside a square, instead of a “D”. GSM
handsets use a removable ‘smart card’ known as SIM, which is found under the battery. Other detailed
differences can be found in the owner’s manual for the specific handset functions.
In addition to the above criteria, there will be a separate part number for each type of handset.
Reference the Mercedes-Benz/Motorola website for part numbers and availability according to zip
code.
1.0 General Section
Mercedes Benz Technical Manual for Telephone v4.6 Date: 09/01/2004