1 – 6
Operation
1.4
SIM Interface
The primary connection to the SIM910 JFET Preamp is the rear-panel
DB–15 SIM interface connector. Typically, the SIM910 is mated to
a SIM900 Mainframe via this connection, either through one of the
internal mainframe slots, or the remote cable interface.
It is also possible to operate the SIM910 directly, without using the
SIM900 Mainframe. This section provides details on the interface.
The SIM910 has no internal protection against reverse polarity, missing
CAUTION
supply, or overvoltage on the power supply pins. Misapplication of power
may cause circuit damage. SRS recommends using the SIM910 together
with the SIM900 Mainframe for most applications.
1.4.1
SIM interface connector
The DB–15 SIM interface connector carries all the power and commu-
nications lines to the instrument. The connector signals are specified
in Table 1.1
Direction
Pin
Signal
Src
⇒
Dest
Description
1
SIGNAL GND
MF
⇒
SIM
Ground reference for signal
2
−
STATUS
SIM
⇒
MF
Status
/
service request (GND
=
asserted,
+
5 V
=
idle)
3
RTS
MF
⇒
SIM
HW Handshake (
+
5 V
=
talk; GND
=
stop)
4
CTS
SIM
⇒
MF
HW Handshake (
+
5 V
=
talk; GND
=
stop)
5
−
REF 10MHZ
MF
⇒
SIM
10 MHz reference (no connection in SIM910)
6
−
5 V
MF
⇒
SIM
Power supply (no connection in SIM910)
7
−
15 V
MF
⇒
SIM
Power supply (analog circuitry)
8
PS RTN
MF
⇒
SIM
Power supply return
9
CHASSIS GND
Chassis ground
10
TXD
MF
⇒
SIM
Async data (start bit
=
“0”
= +
5 V; “1”
=
GND)
11
RXD
SIM
⇒
MF
Async data (start bit
=
“0”
= +
5 V; “1”
=
GND)
12
+
REF 10MHz
MF
⇒
SIM
10 MHz reference (no connection in SIM910)
13
+
5 V
MF
⇒
SIM
Power supply (digital circuitry)
14
+
15 V
MF
⇒
SIM
Power supply (analog circuitry)
15
+
24 V
MF
⇒
SIM
Power supply (no connection in SIM910)
Table 1.1: SIM Interface Connector Pin Assignments, DB-15
1.4.2
Direct interfacing
The SIM910 is intended for operation in the SIM900 Mainframe, but
users may wish to directly interface the module to their own systems
without the use of additional hardware.
SIM910
JFET Preamp
