![background image](http://html1.mh-extra.com/html/elpro-technologies/wi-mod-9-d/wi-mod-9-d_user-manual_2396109061.webp)
Appendix A
Hayes Commands
Page
61
S16
0-255
Transmit Hold-off Time
In msec (default = 0)
S17 0-255
Receive Hold-off Time
In msec (default = 0)
S18
0-255
Input buffer delay
Radio will not transmit until the number of
characters in the input buffer = 2 x S18
value - see below
S19
0-255
Input buffer delay override
Override time in msec to override S18 delay
- see below.
S20
0-255
Default system address
S2
1
0-255
Radio message signature /
lead-in tones
0, 1, 2 or 3
default = 1
set to 0 for old systems, set to 2 or 3 for
new systems suffering interference from
other
WI-I/O 9-x
systems
S18 is calculated as
S18 = (MP – (SR * (10*MP/RB + TD)) / 2 (Rounded up)
SB is serial baud Rate, (in
bits
per second)
SR is serial data Rate, (in
bytes
per second – usually 1/10
th
of SB)
RB is radio baud Rate, (in
bits
per second)
TD is transmit delay (0.028 for transparent/controlled mode, 0 for fast controlled mode)
MP is the maximum packet size to be transferred
NB is the maximum number of bit times delay allowed between characters in the protocol.
S19 is calculated as
S19 = 1000 * (NB/SB)
(Rounded up)