1213-05: Zero Suppression; 1213-06: Loopback Mode - NEC DSX Software Manual

12xx-Slots
121x-Lines
1213-T1/E1 Card Setup
Default
• Yes (1) - Enabled

1213-05: Zero Suppression

(B8ZS/HDB3)
Use this option to enable or disable zero suppression for the PCB transmit path.
If enabled, T1 PCBs use B8ZS zero suppression, while E1 PCBs use HDB3 zero suppression.
If disabled, the PCB has no transmit zero suppression. (Note the receive zero suppression is always enabled.)
Zero suppression may help prevent T1 PCB clocking problems, but should always be set for compatibility
with the connected telco.
Features
• T1 Lines (page 338)
IntraMail Features
• None
Options
• No (0) - Disabled
• Yes (1) - Enabled
Default
• Yes (1) - Enabled

1213-06: Loopback Mode

(Loopback Mode)
Use this option to enable T1 PCB loopback. Although loopbacks are generally used for factory testing, you may
find Remote and Payload Loopback helpful for on-site troubleshooting. The available loopback entries are:
None
Loopback is not enabled.
❥
Metallic
This option loops the T1 PCB internal analog output to the PCB internal analog input. The PCB external
❥
(telco side) connection is isolated during this test. Metallic Loopback is not normally used as a field test.
Digital
This option loops the T1 PCB internal digital output through the PCB's framer chip and then back to the
❥
PCB internal digital input. Digital Loopback is not normally used as a field test.
Remote
This option loops any analog signal on the T1 PCB external (telco side) receive tip and ring to the exter-
❥
nal (telco side) transmit tip and ring. Remote Loopback may be useful for field testing because it loops
any analog test signal on the PCB receive tip and ring back to the transmit tip and ring.
ST-Bus
This option loops the T1 PCB internal digital output to the PCB internal digital input. It does not loop
❥
back through the framer chip. ST-Bus Loopback is not normally used as a field test.
Payload
This option loops any digital signal on the T1 PCB external (telco side) receive tip and ring to the exter-
❥
nal (telco side) transmit tip and ring. Payload Loopback may be useful for field testing because it loops
any digital test signal on the PCB receive tip and ring back to the transmit tip and ring.
Features
• T1 Lines (page 338)
IntraMail Features
• None
618 ◆ System Options: 1001-1702
DSX Software Manual