7300 Timing

Serial Cards

The 7300 serial cards can be clocked Internal, External, ExtInt, and ExtLp with no restrictions between ports or speeds up to 8,196,000bps. These timing modes are the same as other standard Vanguard products. The recommended Timing configuration for all applications is ExtInt on the DCE side and ExtLp on the DTE side (except for X.21). This is required for all higher speed connections to work reliably.

	7300 port as a DCE	7300 port as a DTE
Internal	Uses an internal oscillator and provides clock on both the Transmit and Receive Clock lines.	Uses an internal oscillator to provide clock on the External Transmit Clock line. Expects a clock supplied by the attached device on Receive Clock line.
External	Expects a clock on External Transmit Clock line supplied by the attached device. Uses an internal oscillator to provide clock on the Receive Clock line.	Expects a clock supplied by the attached device on both Transmit and Receive Clock lines.
ExtInt	Uses an internal oscillator to provide clock to the attached device on the Receive Clock line. Expects the attached device to loop the Receive Clock around and provide it on the External Transmit Clock line.	N/A
ExtLp	N/A	Expects the attached device to provide a clock on Receive Clock line and will loop this clock around and provide it on the External Transmit Clock line.

T1/E1 Card

The T1/E1 card has three groups of 4 ports (2 groups for an 8 port card). Each T1/E1 card can have a maximum of 3 different time bases on a single 12 port card (2 for 8 port cards), one on each of the groups.

The Time base for all four ports in each group must be the same, either from an external source within the group, another group, another card or an internal oscillator. You can set each port to Internal, Primary External (Prim_Ext), or Secondary External (Sec-Ext). This setting determines whether the attached device provides the timing or accepts timing from each port and also sets the priority of this clock.

There are three types of clock buses in the node, Group Clock, Card Clock and System Clock. There are three Group Clock busses on each twelve port card (two for 8 port cards), one for each group of four ports. This locks the timing of each of the four ports in a group together.

There is one Card Clock on each card. Card Clock allows you to lock multiple Groups together and must be used for voice ports.

There is one System Clock in the node, which allows you to lock multiple cards together.

You set each group on a card (four ports) as to whether it participates in Card Clock or not and you set the card as to whether it participates in System Clock.

The following depicts this arrangement with X’s where these connection points are located:

If you have an external device providing a clock to a port, that clock, if it is the first, highest priority clock in the group with drive Group clock. You can configure Group Clock to drive Card Clock. Card Clock can then be used to synchronize different Groups and/or to drive System Clock. System clock can be used to synchronize multiple cards.

If you are running Voice, the PCM encoded port must be on ports 1-2 (1-4 future) and the Group must be set to Card Clock.

Port Timing	Group Clock set to Group Clock	Group Clock set to Card Clock	Card Clock set to System Clock
Internal	All four ports are isolated from other groups. Port used Group Clock for transmit and expects the remote device to return this clock. NOTE: If all ports in the group are internal, the ports will uses Card Clock for their transmit.	Card Clock drives Group Clock’s transmit. NOTE: Group must be set to Card Clock for voice connections.	System Clock drives Card Clock’s transmit. NOTE: Do not set all ports to Internal when set for system clock or there will not be a master clock source and connections will not operate properly.
Sec-Ext	External device provides a clock to this port and if it is the highest priority port that is synchronized, drives Group Clock	External device provides a clock and if it is the first highest priority port synchronized, drives Card Clock. NOTE: Group must be set to Card Clock for voice connections.	External device provides a clock and if it is the first highest priority port synchronized, drives System Clock.
Prim-Ext	External device provides a clock to this port and if it is the highest priority port that is synchronized, drives Group Clock.	External device provides a clock and if it is the first highest priority port synchronized, drives Card Clock. NOTE: Group must be set to Card Clock for voice connections.	External device provides a clock and if it is the first highest priority port synchronized, drives System Clock.

T1 Clock Configuration

The Port Timing parameter is configured on each T1 port as shown below.

Port Timing:

Range = PRIM_EXT,SEC-EXT,INTERNAL

Default = SEC-EXT

Configures whether timing is provided to or received from this port and

the priority of the received timing to become the source of the Group,

Card or System clock as configured in the Tx Network Clock Configuration.

PRIM-EXT : This port is connected to T1/E1 network that provides

timing. Timing derived by this port may be used as the highest

priority timing source to the Group, Card or System Clock.

SEC-EXT : This port is connected to T1/E1 network that provides

timing. Timing derived by this port may be used as timing source to

the Group, Card or System Clock if no PRIM_EXT is available.

INTERNAL : This port is connected to T1/E1 network that needs to

be provided with timing. The timing is derived from the Group,

Card or System Bus.

The Network Clock configuration, Card Clock and System Clock, is configured on each T1 card. The entry number in the Network clock configuration table is the same as the card slot number. For example, if you have a T1 card in slot 3, you would configure Entry Number 3 for that card. The following show the configuration and help screens.

Tx Network Clock Selection Table Configuration

Entry Number is the number of the card slot to be configured.

Entry Number: 1/2

[2] Card Clock Participation: NONE/

[2] Group 1 Clock Participation: CARD_CLOCK/

[2] Group 2 Clock Participation: CARD_CLOCK/

[2] Group 3 Clock Participation: CARD_CLOCK/

[2] Card Clock Participation: NONE/?

Range = NONE,SYSTEM_CLOCK

Default = NONE

Specifies whether this card participates in System Clock election.

System Clock election uses first, highest priority port timing that

is not in alarm to drive the System Clock bus to which all other ports

can be locked. Other port timing sources will be used if they go out

of alarm and have a higher priority, or if the current source goes

in to alarm. Port transmit clock is derived from Group, Card, or

System Clock, depending on the Card Clock Participation and Group

Clock Participation configuration.

NONE : Card does not participate in System Clock.

SYSTEM_CLOCK : Card participates in System Clock election.

[2] Group 1 Clock Participation: CARD_CLOCK/?

Range = GROUP_CLOCK,CARD_CLOCK

Default = CARD_CLOCK

Specifies whether Group 1 participates in Card Clock.

GROUP_CLOCK : T1E1 ports x01-x04 do not participate in Card or

System Clock election. This isolates all four ports

of the group from the Card or System Clock. If all

four ports are set to Internal, the clock provided

to the ports is from one of the ports internal

oscillator.

CARD_CLOCK : T1E1 ports x01-x04 participate in Card or System

Clock election.

[2] Group 2 Clock Participation: CARD_CLOCK/?

Range = GROUP_CLOCK,CARD_CLOCK

Default = CARD_CLOCK

Specifies whether Group 2 participates in Card Clock.

GROUP_CLOCK : T1E1 ports x05-x08 do not participate in Card or