SSR-1U User’s Manual
Rev -, 27 Dec 2019
© 2019 Slerj, LLC
7
www.slerj.com
2.4
Connecting the SSR-1U
The pins of the main connector are shown in Figure 3 and described in Table 1. The pins of the
auxiliary connector are shown in Figure 4 and described in Table 2. The default configuration of
the SSR-1U provides access to the user shell (see Section 4 Interactive Shell, for details) on
channel 4 (aux connector) and causes channels 1, 2 and 3 to record when the digital input
command pin (DI, pin 15) is pulled to ground. All channels default to 115200 baud, 8 data bits,
no parity, and 1 stop bit.
WARNING: Channels 1 and 2 are RS-232 voltage level compatible, and channels 3
and 4 are 5 Volt tolerant, TTL compatible, 3.3V CMOS. Do not connect an RS-232
device to channel 3 or 4 of the SSR-1U.
Figure 3. Main Connector (View looking into the face of the connector)
Table 1. Main Connector Pins
Pin
1
ID
Description
1
Vsup
Supply voltage (4.5-32 VDC).
2
Vret
Supply return (tied to GND onboard the SSR-1U).
3,7
2
T1,T2
Asynchronous serial transmitter output for channels 1 and 2.
4,8
2
R1,R2
Asynchronous serial receiver input for channels 1 and 2.
11
3
T3
Asynchronous serial transmitter output for channel 3.
12
4
R3
Asynchronous serial receiver input for channel 3.
16,18,20
3
S
x
Status indication for channel
x
. High level indicates that the channel is
recording.
15
4
DI
Digital input record command.
17
4
PI
PWM input record command.
19
4
res
Reserved.
1
See Section 7.1 Electrical for detailed electrical specifications.
2
RS-232 compatible (SR122T). For the SR1CCT, these are 3.3V CMOS (not 5V tolerant).
3
3.3V CMOS output
4
5V tolerant, TTL compatible, 3.3V CMOS input. Internally pulled up to 3.3 VDC.