IP Relay HWg-ER02b - Manual
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====== Serial Setup ======
&B: Speed
9600
Sets the communication speed for the serial line. Any speed from 50 to 115,200 Bd can be set. To set
9600 Bd, enter at the command prompt:
“&B9600”. The resolution depends on the speed. Up to about
1000 Bd, 1 Bd steps can be used. At 10 kBd, only 100 Bd steps are still usable.
&D: Data bits
8
Number of data bits in the serial communication.
7: 7 bits
/
8: 8 bits
– for instance, to set 8 data bits, enter “&D8”.
&P: Parity
NONE
Parity of the serial asynchronous communication.
For example, to configure communication without parity, enter “&PN”.
N: none
/
O: odd
/
E: even
/
M: mark
/
S: space
&V: Variable Parity Parity
Off
Supplemental function for 9-bit protocols. Only the difference from the pre-set parity bit value is
transmitted. For correct operation, a parity needs to be set (usually Mark/Space). A double 0xFE
character followed by “P” is used to transfer the difference from the pre-set parity. In this mode, the
0xFE character is a prefix; if it appears within the data stream, it needs to be doubled. This option is
recommended for the box-2-box mode (two converters connected back-to-back) and 9-bit protocols.
Off:
incorrect parity bit ignored
On:
incorrect parity bit transmitted to the other device
For instance, to set up 9-
bit communication with a majority of data having “space parity”, enter:
“&PS;&V1” (space variable parity on).
&M: Multidrop mask
(0 = DISABLE Multidrop)
&N: Multidrop network address
Evaluates parity errors at the serial line. &V1 Variable parity must be enabled and a parity must be
set. Usual settings are 8 bits, SPACE, 1 stop bit.
At the beginning, nothing is transferred from the serial line and the device waits for a byte with
“incorrect” parity; usually 8 MARK 1.
When such a byte is received, it is masked with &M and compared with &N (<received byte> AND
&M == &N). If true, data transfer is enabled. 0xFE 'P' + received byte is inserted before the data.
Then, data is transferred in a transparent manner, until another byte with “incorrect” parity is
received.
When such a byte arrives, it is tested. If the test fails, the COM->TCP transfer is stopped and the
device waits for another byte with “incorrect” parity. This invalid “address“ byte nor other marks are
sent over TCP.
In other cases, the configured address is sent to the TCP channel as defined by the variable parity
protocol
– <0xFE><P><address>. The transfer is stopped as soon as another byte with the 9th bit set
(modified parity) is received.
