The various phones have different ICs in them, when shipping. This is an (incomplete) overview.

Owner Device Revision Firmware IC 1 Firmware IC 2 Voiceware IC 1 Voiceware IC 2 Additional
Foulab Multipay “2.0” SMD U2: M29F040B (4MBit) X1: M29F040B (4MBit) U16: M27C801 (8MBit) U26: M27C801 (8MBit)
Martin Multipay “Nevada” “1.0” THT U5: M27C2001 (2MBit) n/a U10: M27C4001 (4MBit) n/a
Martin Multipay “Bell”/TTY “1.5” THT U5: unknown n/a U10: unknown n/a, perhaps –> U22: unknown
Sam Multipay “Bell” “1.5” THT U5: M27C2001 (2MBit) n/a U10: AT27C040 (4MBit) n/a, perhaps –> U22: unpopulated
TP Deskset Rev 2 U22: M27C2001 (2MBit) n/a U35: M27C4001 (4MBit) n/a
Martin Deskset “Bell” Rev 2 U22: unknown n/a U35: unknown n/a

Controlboard Revisions

The controlboard-revisions mentioned here probably do not conform to official Nortel-numbering.

Device Revision Remarks
Multipay 1.0 THT All components Through-Hole, only 2 IC-sockets for firmware and voiceware.
Multipay 1.5 THT Same PCB as 1.0 THT, but added second IC-socket below the first voiceware-socket. Nevertheless new socket seems not to be in use. Found in two Bell-Multipays, one of them refurbished and with TTY-keyboard.
Multipay 2.0 SMD All components SMD, features 2 firmware and 2 voiceware-ICs in PLCC-packages. Phone can download additional applications to run on the phone.
Deskset Rev 1 The two IC-sockets for firmware and voiceware are placed diagonally from each other.
Deskset Rev 2 The two IC-sockets for firmware and voiceware are placed one below the other. Board is still marked “Rev. 1”.

ICs and their replacements

IC Type Description Used for Replaceable with
M29F040B plcc32 4MBit (512Kb x 😎 Flash 2.0 SMD Firmware Same type
M27C801 plcc32 8MBit (1Mb x 😎 OTP EPROM 2.0 SMD Voiceware to be determined
M27C2001 DIP32 2MBit (256Kb x 😎 OTP EPROM 1.x THT Firmware SST39SF020A (Flash)
M27C4001 DIP32 4MBit (512Kb x 😎 OTP EPROM 1.0 THT Voiceware W27E040 (EEPROM)
AT27C040 DIP32 4MBit (512Kb x 😎 OTP EPROM 1.5 THT Voiceware W27E040 (EEPROM)
M27C2001 plcc32 2MBit (256Kb x 😎 OTP EPROM Deskset Firmware SST39SF020A (Flash)
M27C4001 plcc32 4MBit (512Kb x 😎 OTP EPROM 1.0 THT Voiceware W27E040 (EEPROM)

Please realize, that the W27E040 EEPROM cannot be substituted for a SST-series Flash, as the 040 and upwards capacities are not pin-compatible (Check the top row, pin A18, etc.)
The Winbond W27E040 is available in a DIP-32 as well as a PLCC-32 packaging - but unfortunately almost exclusively only through 3rd party sellers like AliExpress and eBay.
You may save yourself the trouble and just use a regular OTP-EPROM for the voiceware, if you're not planning on changing it.

For testing purposes, on the desk series of phones (and perhaps others), an ST Microelectronics M29F040B and likely others may replace the original voiceware EPROM. While it'll work, the bank switching circuitry will only recognize the final 2 mbits of the ROM, where foreign language prompts would normally go. In order to test accurately, it's necessary to put the tone and pause samples in the same places where they'd normally be within the first mbit.

  • millennium/ics.txt
  • Last modified: 2021/04/18 12:35
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