P300H P300 Series Modem Installation and Operating Handbook Page 172
P1440 IN V.35 MODE
The P1440 is the standard interface supplied with the P300 Series Modem. If
V.35
is selected under
ݸ¿²¹»
,
Ì»®®óײ¬º½
,
Û´»½¬®·½¿´
then the following interface description applies.
Min
Req
Signal Description
V.35
Name
Circuit
Number
25 pin
37 pin
Electrical
Levels
Old Style
Winchester
A
B
A
B
DATA CIRCUIT TOWARDS MODEM (TX)
Clock In
SCTE
113
24
11
17
35
V.35
U & W
Data In
SD
P & S
103
2
14
4
22
V.35
Sig
`
Valid In
RTS
105
4
7
RS232
C
Sig Accpt
`
d Out
CTS
106
5
9
RS232
D
Int
`
Tx Clock Out
SCT
114
15
12
5
23
V.35
Y & aa
DATA CIRCUIT FROM MODEM (RX)
Clock Out
SCR
115
17
9
8
26
V.35
V & X
Data Out
RD
104
3
16
6
24
V.35
R & T
Sig
`
Valid Out
RLSD
109
8
13
RS232
F
COMMON LINES
Signal Ground
SG
102
7
19, 20, 21
Ground
B
Shield/Protective ground
FG
101
1
1
Screen
A
Device (DTE) Ready In
DTR
108
RS232
20
12
H
Device (DCE) Ready Out
DSR
107
6
11
RS232
E
Local Loop In
LL
141
18
10
RS232
-
Remote Loop In
RL
140
-
21
14
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
̨
Ý´±½µ ײ
the `Data In` signal is checked against the `Clock In` signal. With the Tx Clocking Set to
ײ¬»®²¿´
or
Ψ
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. If you require the older 34-pin
`Winchester` connector then an adaptor lead is required, please contact the factory for details.
By selecting
ݸ¿²¹»
,
Ì»®®óײ¬º½
,
ݱ²¬®±´ Ô·²»-
it is possible to configure the modem to raise an alarm if either the
`Sig Valid In` line (RTS) or `Device (DTE) Ready In` line (DTR) 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 (RTS) by selecting
ݸ¿²¹»
,
̨
,
Ó±¼«´¿¬±®
,
Ý¿®®·»®
,
ÎÌÍóݱ²¬®±´´»¼
.