Inside a Philips NMS 3000 Telematico

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Specifications / Design

NMS 3000 TELEMATICO

- Design : Celint UK (United Kingdom - Company activity : 1986.12.04 -> 2002)

- Unit from November 1989

- Z80A CPU - Clock: 3 MHz

- 8 kB ROM

- 2 kB System RAM

- PCD8582 256 Bytes I2C EEPROM

- EF7910 FSK Modem - Clock: 2.457 MHz

- 8255 3*8bits I/O.
Original ROM 8255 configuration : 0x99

8255 Pinout mapping :

PA0-PA7: In, Keyboard
PB0: Out, EEPROM SDA + Modem Tx Data Line (Before 7SLS155 Demux)
PB1: Out, EEPROM SCL
PB2: Out, Modem MC0 + MC1 (MC2 to VCC , MC3 and MC4 to VSS)
PB3: Out, MR9735 chip select
PB4: Out, - 74LS08 gate.
PB5: Out, Relay 2 (Pick up / dialing) + 74LS08 gate + Green LED...
PB6: Out, Relay 1 (dialing mode)
PB7: Out, Video related ... Drive one 74HC245 data line ?
PC0: In, Modem Rx Data Line
PC1: In, Modem Carrier detect (Active Low)
PC2: In, Phone Line status (Line presence, Optocoupler)
PC3: In, Strap ? (Connected to VSS)
PC4: In, EEPROM SCL
PC5: In, EEPROM SDA
PC6: In, MR9735 TS2 output
PC7: In, MR9735 TS1 output

- MR9735 TELETEXT/VIEWDATA VIDEO GENERATOR - Clock: 6 MHz

- 2 kB Teletel Video RAM (CPU / MR9735 Muxed access)

- Power Supply : +5V (600mA), -5V (50mA), +10V (100mA) (regulated into the PSU bloc)

- Main power consumption (Measured): 8 Watts, Power factor : 0.58

- Transport : V.23 (High state : 1300 Hz, Low state : 2100 Hz) - 1200 Baud - 1 start bit, 7 data bits - Even parity bit, 1 stop bit. Pulse dialing.

System memory mapping:

0x0000 - 0x7FFF : ROM (Mirrored 8k / 0x2000 bytes)
0x8000 - 0xBFFF : MR9735 Teletex RAM (Mirrored 2k / 0x800 bytes)
0xC000 - 0xFFFF : System RAM. (Mirrored 2k / 0x800 bytes)

System I/O mapping:

0x00 - 0xFF : 8255

Interrupts sources:

NMI: Disabled (connected to VCC)
Normal Interrupts: 4800 Hz Pulses derived/generated from the MR9735 19.2kHz output.