OPTION DESCRIPTIONS
1.3 HANDSHAKING
1.3.1 DCE
HANDSHAKING
This module is expecting at least two signals from the user’s equipment: DTR and RTS. A third
possibility would be TXD and it would only be used in the asynchronous mode. When the DTR
signal is not active, the DSR and CTS signals will both be inactive and this module will not send
any time messages. When the DTR signal goes active, the DSR and CTS signals will both go
active. A time message will be transmitted only when both DTR and RTS are both active. If RTS
goes inactive while a time message output is in progress, the time message output will be paused
until RTS returns to active, at which time the time message will resume. A partial message can be
cleared by setting DTR inactive.
1.3.2 DTE
HANDSHAKING
This module is expecting at least two signals from the user’s equipment: DSR and CTS. A third
possibility would be RXD and it would only be used in the asynchronous mode. When the DSR
signal is not active, the DRT and RTS signals will both be inactive and this module will not send
any time messages. When the DSR signal goes active, the DTR and RTS signals will both go active.
A time message will be transmitted only with DSR and CTS are both active. If CTS goes inactive
while a time message output is in progress, the time message output will be paused until CTS
returns to active, at which time the time message will resume. A partial message can be cleared by
setting DSR inactive.
1.4
MODE OF OPERATION
There are two modes of operation possible with this module:
Synchronous
(burst), and
asynchronous
(demand/response). The
synchronous
mode provides a time message at regular
intervals selected by the user. The
asynchronous
mode outputs a time message upon receipt of a
predefined character. The 8 bit image of the demand character is set by the user by means of an 8
bit DIP switch.
1.4.1 SYNCHRONOUS
MODE
This module is capable of providing time messages at five different rates:
Ten messages per second.
One message per second.
One message per ten seconds.
One message per one-hundred seconds.
One message per 1000 seconds.
1.4.2 ASYNCHRONOUS
MODE
When this module is set up in the asynchronous mode the time output rates described in
“Synchronous Mode” will be ignored. The user must select an 8 bit character (any hex value from
00 to FF) as a time demand character. The user sends the selected character to this module, which
causes a time message to be output in response.
Note:
When a switch is set to the “ON” position, the voltage for that line is 0
volts or low. In other words, ON = Binary Zero; OFF = Binary One.
Symmetricom, Inc.
TM7000 TymMachine TCG/T (Rev D)
A-15
