16.2
SPECIFICATIONS
As of the date this manual was published, the following specifications apply to all RFL 9785
Checkback modules. Because all RFL products undergo constant refinement and improvement, these
specifications are subject to change without notice.
Codes:
Capable of transmitting and receiving 16 asynchronous codes (01 through 16)
Test Log:
Available through RS-232 port or optional Checkback Alarm Chassis (See
Section 20)
Test/Fail Output:
Solid-state relay, rated for 1 ampere.
16.3
TYPICAL CHECKBACK APPLICATION
A two-terminal line (Figure 16-5a) can be programmed with the RFL 9785 to perform the test
sequence shown in Figure 16-5b. The Master station will initiate the test automatically once every 24
hours, starting 3 hours after the unit is programmed. Tests can also be initiated manually, or by
external input. Each terminal is tested at both full-power and reduced-power levels, and each terminal
can send a continuous carrier upon request from the other terminal (Figure 16-5c).
STATION A
STATION B
MASTER
REMOTE
A. One-line diagram.
STATION A - MASTER
1
TX 01
RX 01
2
TX 02
RX 02
B. Checkback test routine.
STATION A
MASTER
HC 1
TX 03
RX 04
TX HC
TX 05
RX 06
TX HC
HIGH
HIGH
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
LOW
STATION B - REMOTE
RX 01
TX 01
RX 02
TX 02
STATION B
REMOTE
RX 03
TX HC
TX 04
RX 05
TX HC
TX 06
C. Hard carrier request routines.
LOW
HIGH
HC 1
HC 2
HC 2
KEY:
TX 01 CODE SENT
RX 01 CODE RECEIVED
TX HC HARD CARRIER SENT
TEST CODE OR HARD CARRIER REQUEST
HARD CARRIER
Figure 16-5. Checkback testing of typical two-terminal system
RFL 9785
RFL Electronics Inc.
July 26, 2007
16-3
(973) 334-3100