Ericsson T28 – the slimmest phone of 1999, still a legend

Ericsson T28 – the thinnest phone of 1999, still a legend

The Ericsson T28 was unveiled in 1999 and stunned the world with its incredibly slim profile: just 15 mm when closed — an absolute record for the time that no competitor managed to match for years. Its elegant lines, innovative lithium polymer battery and flip mechanism made it immediately an object of desire. To this day it remains one of the most sought-after vintage phones among collectors worldwide.

Complete Technical Specifications

Feature    Detail
Year    1999
Network    GSM 900/1800 MHz (Dual Band)
Display    4-level greyscale LCD — 101 x 33 pixels
Battery    Li-Pol (lithium polymer) 500 mAh
Weight    83 grams
Dimensions open    147 mm
Dimensions closed    95 x 50 x 15 mm
Phonebook    200 contacts
Connectivity    Infrared IrDA
Features    Calendar, calculator, alarm, polyphonic ringtones
WAP    Only on some operator versions
SIM    Mini-SIM (2FF)
Variants    T28 / T28s (extended memory)

Design and Materials

High-quality polycarbonate body, backlit keyboard and fold-open flip that protected the keypad when closed. Open it measured 147 mm, closed just 95 mm at 83 grams — extraordinary for the era. The Li-Pol battery was one of the first ever used in a commercial mobile phone, thinner and lighter than the previous NiMH batteries.

Verified Secret Codes

Main service menu:
>*<<*<* (right key, asterisk, left key, left key, asterisk, left key, asterisk)
Opens the hidden Ericsson service menu. The < and > symbols correspond to the left and right arrow keys on the phone.

*#06# → Display IMEI number

Universal GSM codes:
**04*[old PIN]*[new PIN]*[new PIN]# → Change PIN
**05*[PUK]*[new PIN]*[new PIN]# → Unlock SIM with PUK
*43# / #43# / *#43# → Call waiting ON / OFF / Status
*21*[number]# / #21# / *#21# → Unconditional forwarding ON / OFF / Status
*61*[number]# → Forward if no answer
*62*[number]# → Forward if unreachable
*67*[number]# → Forward if busy
##002# → Deactivate all forwarding

Common Issues and Solutions

Battery not holding charge — original Li-Pol batteries after 25 years are almost all depleted. Modern compatible batteries exist in original dimensions.

Broken flip or weak hinge — the hinge is the most vulnerable point. Repair with epoxy glue is possible or replacement with spare parts still available online.

Keys not responding — cleaning contacts under the keys with 99% isopropyl alcohol and a fine brush resolves the issue in most cases.

No GSM signal — check that the SIM supports GSM 900/1800 MHz. SIM cards that are only 3G/4G are not compatible.

Collector Value 2026

Condition    Indicative value
Broken or for parts    €10-25
Working with issues    €30-60
Good condition with working battery    €80-150
Very good condition with intact flip    €120-200
Mint with original box and accessories    €200-350

The T28s is worth approximately 15-20% more in the same conditions. Models with original box and complete accessories are the most sought after.

Why Buy at Infosate

Every Ericsson T28 sold at Infosate has been verified and tested before shipping. We have been selling vintage phones since 2007 — over 2,348 positive feedback on eBay, Top Rated Seller. Professional packaging with bubble wrap and tracking included throughout Europe.