ArchitectureProperty Management System - Communication Interface
Timers | The following timers are used to maintain data transmission: |
Sender Timer
Upon sending a start sequence, message text or query, this timer begins counting and stops counting upon receiving a valid answer control code. This timer is set to one (1) second. If a timeout occurs after the transmission of a start sequence, a start sequence will be resent up to 15 times. If a timeout occurs during the transmission of a message text or query, a query is sent up to 32 times.
Cabling Considerations
Receiver Timer
Upon transmission of a positive acknowledgment for a start sequence or a message text, this timer begins counting and stops counting upon receiving a message text or an end code. This timer is set to 35 seconds. If a timeout occurs, the sender loses send rights.
When the PMS is connected to the NEAX through a modem, the cables should just be “straight through” cables. There should be no crossing.
When the PMS is directly connected to the NEAX, use the following pin assignments:
NEAX |
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Pin No. | Signal |
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1 | FG |
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2 | SD |
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3 | RD |
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4 | RS |
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5 | CS |
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6 | DR |
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7SG
8CD
20ER
PMS
Signal Pin No.
FG 1
SD 2
RD 3
RS 4
CS 5
DR 6
SG 7
CD 8
ER 20
Figure 2-4 Direct Connection Pin Assignments
Bisynchronous (BSC) Transmission
Line Control | The characteristics of the signals transmitted across the communications link are as |
Characteristics | follows: |
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