Q-Flex Satellite Modem Installation and Operating Handbook
9-6
EIA-530 Interface in V.35 Mode
The EIA-530 interface is used inV.35 mode as follows.
Min
Req
Signal Description
V.35
Name
Circuit
Number
25 pin
Electrical
Levels
Old Style
Winchester
A
B
DATA CIRCUIT TOWARDS MODEM (TX)
Clock In
SCTE
113
24
11
V.35
U & W
Data In
SD
103
2
14
V.35
P & S
Sig
’
Valid In
RTS
105
4
RS232
C
Sig Accpt
’
d Out
CTS
106
5
RS232
D
Int
’
Tx Clock Out
SCT
114
15
12
V.35
Y & aa
DATA CIRCUIT FROM MODEM (RX)
Clock Out
SCR
115
17
9
V.35
V & X
Data Out
RD
104
3
16
V.35
R & T
Sig
’
Valid Out
RLSD
109
8
RS232
F
COMMON LINES
Signal Ground
SG
102
7
Ground
B
Shield/Protective ground
FG
101
1
Screen
A
Device (DTE) Ready In
DTR
108
20
RS232
H
Device (DCE) Ready Out
DSR
107
6
RS232
E
Local Loop In
LL
141
18
RS23
2
-
Remote Loop In
RL
140
21
RS23
2
-
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.
If you require the older 34-pin `Winchester` connector then an adaptor lead is required -
please contact the factory for details.
