Paradise P300 specifications Eurocom D/1 interface `D` operation

Data Out

Clock Out

* Links

All links settings are:

Centre tap grounded: 1-2 (link `up` with the PCB legend the right way up) Centre tap floating 2-3 (link `down` with the PCB legend the right way up)

The typical configuration would normally be to ground the outputs, and leave the inputs floating ie: Links 4, 5, and 7 in pos 1-2 (up), and links 1 and 2 in pos 2-3 (down)

This provides protection by ensuring the signal levels remain close to ground potential (as might happen if both inputs and outputs were floating), but avoid any ground currents between distant locations (as might happen if both inputs and outputs were grounded).

The modem will detect and display the `Data Marginal` warning if the Tx input clock and data phase is incorrect, and will automatically flip the clock phase to correct this. If repeated `Data Marginal` alarms occur then it is likely the Tx clock and data are not from the same clock course and are `slipping past` each other.

U

COMMON LINES

Ground to Activate Eurocom `D`

Do Not Connect

Signal Ground

Shield/Protective ground

Data In

Clock In

SG

PG

102

101

n/a

n/a

n/a

n/a

14

12, 20

2, 7, 13, 15, 22, 25

1

16

LK 5 *

RD

104

3

LK 4 *

4

RT

115

17

19

18

21

TT

SD

ST

113

103

114

LK 1 *

LK 2 *

LK 7 *

6

5

8

transformer

A

B

Name

Number

centre tap of

RS422

Circuit

25 pin

Link to ground

Eurocom D/1 interface `D` operation

The Eurocom `D` interface uses transformer coupled differential clock and data signals. The data signal is AMI coded, and the amplitude of both clock and data signals is ±0.5V (ie 1.0 V peak to peak). The differential lines are of 130 impedance, and the centre tap of the line coupling transformers may either be grounded, or left floatingS.

The Eurocom `D` interface will operate from <16kbps to >2048kbps, although the Eurocom specification call for only 256, 512, and 1024kbps. In addition to the clock and data lines in and out (four lines), a fifth line is implemented over and above the Eurocom specification which carries the modems internal clock out when the Tx clock is set to internal.

Min

Signal Description

Req

DATA CIRCUIT TOWARDS MODEM (TX)

Int’ Tx Clock Out

DATA CIRCUIT FROM MODEM (RX)

P300H P300 Series Modem Installation and Operating Handbook Page 177