View Full Version : Modem For GRiD 1720/1750/1720/1660C/1680/1680C - Drivers? Information?

April 10th, 2020, 01:32 PM
Does anyone know anything about a modem that is compatible with the GRiD 1720/1750/1720/1660C/1680/1680C? They all use the same modem interface, so the one I found seems to be compatible with all of them. It came out of a GRiD 1755. I have confirmed physical compatibility with the 1720/1750/1755.

It's model number is "G20-0341". FCC ID: EVZMODEM4NOTEBOOK. FCC Registration: EVZUSA-73462-FA-E.

The card says "DataRace 1992" right on the PCB. It also says "GRiD 8493070 FW 4.10RA0" on a sticker on top of a chip.

From what I can read off of it, it's a 14.4 kbps w/ fax (It says "v32 BIS w/Fax" on the modem).

It's a very interesting design. It's two stacked board, with surface mounted chips on both sides of both boards. Seems like they were trying their hardest to made a compact design. Very nicely done. It has an ATT DSP, for that time period, that is a nice quality chip.

Any help would be appreciated.

May 9th, 2020, 06:23 AM
GRiD V.32bis 14400 Bps Modem Specifications

Communication Modes
Asynchronous, Autosync, Group III FAX
Communication Rates and Communication Standards Supported

300 bps Bell 103
300 bps CCITT V.21
1200 bps Bell 212A
1200 bps CCITT V.22
2400 bps CCITT V.22bis
4800 bps CCITT V.32
7200 bps CCITT V.32bis
9600 bps CCITT V.32
12000 bps CCITT V.32bis
14400 bps CCITT V.32bis

2400 bps CCITT V.27ter
4800 bps CCITT V.27ter
7200 bps CCITT V.29
9600 bps CCIIT V.29

FAX Compatibility
Group III, Class 1

Error Control
Microcom Networking Protocol (MNP) Classes 2 through 4 and V.42 LAP-M

Data Compression
Microcom Networking Protocol (MNP) Class 5 and V.42bis

Command Set
Hayes "AT" command set
Microcom "AT" command subset
EIA-578 Class 1 FAX command set

Operating Modes
Full duplex at %00 bps and below
Half duplex for Group III facsimile

Flow Control
None, RTS/CTS, XON/XOFF (Stop/Start), Transparent XON/XOFF,

Call Progress Monitoring
Dial tone, busy tone, ring detect, answer tone

Dialing Capability
Command-selectable tone or pulse dialing

Command Buffer
40 characters

Receive Levels
-9 to -43 dBm
Transmit Levels
-10 dBm to -9 dBm

Carrier Detection Level
On > -43 dBm and OFF < -48 dBm

Line Requirements
Two-wire switched network (standard telephone line)
Ringer Equivalence: 0.4B

Regulatory Approvals
FCC Part 68
DOC Certified