Specifications

Watson TDM
Operating Manual
Watson-TDM-Manual-W.doc
Version 2.0-01
3-16
Revision: 2008-02-07
3.4.2 Handshake Operation
When no loopback is established, the control circuits perform the following hand-
shake protocol:
• 105 (RTS Request to send, X.21: C): Input from DTE. For X.21, C = OFF will
cause a DTR alarm.
• 106 (CTS Ready for sending, X.21: I):
if Handshake option enabled: is set ON when a DSL connection is estab-
lished and 105 = ON is detected.
if Handshake option disabled: is set ON when a DSL connection is estab-
lished
• 107 (DSR Data set ready): is set ON when a DSL connection is established
• 108 (DTR Data terminal ready): input from DTE. For V.35 and V.36, 108 =
OFF will cause a DTR alarm.
• 109 (RLSD Data channel received line signal detector): is set ON when a
DSL connection is established.
• 140 (RL Loopback / Maintenance test): Input from DTE; will be set OFF in
normal mode.
• 141 (LL Local loopback): input from DTE; will be set OFF in normal mode.
• 142 (TM Test indicator): is set OFF in normal mode.
3.4.3 Supported V.54 Loops
ITU-T recommendation V.54 defines four test loops. Loops 2 and 3 correspond to
DSL loopbacks 2 and 1. The interchange circuits are set in the following way:
• V.54 Loop 2
Loop in remote DCE, i.e. DSL loopback 2 in the remote modem.
The output interchange circuits are set as follows:
Master: 107 = ON and 142 = ON
Slave: 104 (received data) = 1, 106 = OFF, 107 = OFF, 109 = OFF and 142
= ON.
• V.54 Loop 3
Local loop established in the DCE, i.e. DSL loopback 1 in the local modem.
The output interchange circuits are set as follows: 107 = ON and 142 = ON
3.4.4 Automatic Loop Control through the DTE/DCE Interface
Automatic control through the interface is achieved by using circuits 140 and 141:
• 140 = ON and 141 = OFF ⇒ V.54 loop 2 (DSL loopback 2)
• 140 = OFF and 141 = ON ⇒ V.54 loop 3 (DSL loopback 1)
This automatic loop control can be switched on/off using the V54LOOPS monitor
command.