Timewave DSP-232, Operating Manual

Page: 94 / 271

Chapter 5 Packet Operation
Note : Do not attempt multiple packet connections while
FRICK
is active (1-250). In contrast to
FRACK
,
which provides one retry timer per multi-connect channel, there is only one
FRICK
timer in the DSP. Each
channel will try to use the same
FRICK
timer, causing interference to the operation of the other channels.
Due to the sporadic nature of meteor scatter work, a Master/Slave mode can be enabled in the DSP with User BIT
18 (
UBIT 18 ). With UBIT 18 OFF , FRACK operates the same as in previous firmware versions.
With
UBIT 18 ON , a master/slave relationship is established in packet radio connections. This is done to reduce the
possibility of simultaneous transmissions by both sides of a packet connection. In this mode, the master station
sends either an I-frame or a polling frame upon the expiration of
FRICK (or FRACK if FRICK = 0 ). The FRICK or
FRACK
timer then starts counting
again. The master station therefore sends packets constantly, even if all its I-frames have been acknowledged. The
slave station sends nothing, not even I-frames, until it receives a polling frame from the master. A station becomes
the master upon its transmission of a SABM (connect) frame; a station becomes the slave upon its transmission of a
UA (acknowledgement of the SABM) frame.
Recommended settings for this method of meteor scatter work (both stations should use these settings):
UBIT 18 ON
RETRY 0
AX25L2V2 ON (default)
MAXFRAME 1
CHECK (doesn’t matter)
FRICK
n , where n is large enough to allow the other station time to send the start of an
acknowledgement frame
Note : This is an experimental mode and we welcome any comments or suggestions you might have. Please
make them in writing and direct them to AEA’s Engineering Department. Thanks!
FUlldup ON
|
OFF
Default: OFF
Mode: packet Host: FU
OFF Full duplex mode is disabled.
ON
Full duplex mode is enabled.
When full duplex mode is
OFF
(default), the DSP makes use of the DCD (Data Carrier Detect) signal from its
modem to avoid collisions. When,
ON
the DSP ignores the DCD signal and acknowledges packets individually.
Full-duplex operation is useful for full-duplex radio operation, such as through OSCAR satellites. It shouldn’t be
used unless both stations can operate in full-duplex.
GPS Commands are listed in the GPS Operation chapter, Chapter 6
GUSERS
n Default: 0
Mode: packet, AMTOR, PACTOR Host: GU
“ n ” 0 to 3 specifies the maximum number of users allowed to use your node.
GUSERS allows up to
n number of stations to connect to your MYGATE call. The argument “ n ” may be 0-3, with
zero meaning no station can use your node. Alternatively, n can be thought of as the maximum number of pairs of
stations which may be connected through your Gateway.
Your must have your
MYGATE
call entered and GUSERS set to a number greater than 0 to enable the DSPs node
function.
September, 05 5-33