Paradise P300 specifications P1440 in RS422 Mode, Data Circuit Towards Modem TX

P1440 IN RS422 MODE

The P1440 is the standard interface supplied with the P300 Series Modem. If RS422 is selected under Change, Terr-Intfc, Electrical then the following interface description applies.

Min	Signal Description	RS422
Req		Name
DATA CIRCUIT TOWARDS MODEM (TX)

Circuit	25 pin		37 pin		Electrical
Number	A	B	A	B	Levels

	Clock In	TT
U	Data In	SD
	Sig’ Valid In	RS
	Sig Accpt’d Out	CS
	Int’ Tx Clock Out	ST
DATA CIRCUIT FROM MODEM (RX)

113

103

105

106

114

24

2

4

5

15

11

14

19

13

12

17

4

7

9

5

35

22

25

27

23

RS422

RS422

RS422

RS422

RS422

	Clock Out	RT
	Data Out	RD
	Sig’ Valid Out	RR
COMMON LINES

115	17	9	8	26	RS422
104	3	16	6	24	RS422
109	8	10	13	31	RS422

	Signal Ground	SG
U	Shield/Protective ground	PG
	Device (DTE) Ready In	TR
	Device (DCE) Ready Out	DM
	Local Loop In	LL
	Remote Loop In	RL

102

101

108

107

141

140

7

1

2023

6 22

18

21

19, 20, 21

1

1230

1129

10

14

Ground

Screen

RS422

RS422

RS232

RS232

The maximum data rate is 10Mbps (over good quality twisted pair screened cable), but this rate is reduced as the connecting cables extend beyond 10m. As an estimate, assume the maximum rate halves as the distance doubles (ie 5Mbps to 20m, 2.5Mbps to 40m etc).

The input clock/data phase is selected automatically, reporting a `Data Marginal` warning whenever it has to switch phase. If the modem reports Data Marginal frequently then this is not a modem fault but an indication that you have a clocking problem external to the modem (ie changing clock/data phase, a problem which would otherwise have caused untraceable data errors). With the Tx Clocking Set to Tx Clock In the `Data In` signal is checked against the `Clock In` signal. With the Tx Clocking Set to Internal or Rx the `Data In` signal is checked against the `Int’ Tx Clk Out` signal.

Note that although there are both 25 pin EIA530 pinout and 37 pin RS449 pinout connectors on the rear panel, these are simply connected in parallel. Do not use both connectors at the same time.

By selecting Change, Terr-Intfc, Control Lines it is possible to configure the modem to raise an alarm if either the `Sig’ Valid In` line (RS) or `Device (DTE) Ready In` line (TR) switch to the inactive state. It is also possible to configure the Tx carrier to be switched on and off by the `Sig’ Valid In` line (RS) by selecting

Change, Tx, Modulator, Carrier, RTS-Controlled.

P300H P300 Series Modem Installation and Operating Handbook Page 168