E1/T1 PCI card installation guide
24
75 ohm Line Interface
Each network port on the card carries one 30-channel digital service connection. For 75 ohm
characteristic impedance coaxial cables connections, an RJ45 to BNC adapter is required. Each
adapter contains a pair of BNC coaxial connections, one for the transmit cable that is colour
coded white, and one for the receive cable that is colour coded black.
The coaxial adapter is fitted after the card is installed in the host PC. The adapters are only push
fit so some form of strain relief is recommended.
75 Ohm Network Connection
The connection of the network input and output ports on the E1 card to the network termination
port (NTP) must be via coaxial cables with a nominal impedance of 75 ohms terminated with a
75 ohm BNC plug.
Note
There may be maximum cable lengths imposed by the PTO.
The correct identification of the input and output of the network termination ports is the
responsibility of installation personnel.
120 Ohm Line Interface
Each network port on the card carries one 30-channel digital service connection via a screened
twisted pair cable of 120 ohm characteristic impedance. There is one transmit pair and one
receive pair.
120 Ohm Network Connection
The 8-contact RJ45 Telephone Modular Plug on the cable between the card and the network
must be wired as follows:
Pin
Signal
Function
Direction
4 LTT Transmit
(tip) output
5 LTR Transmit
(ring) output
1 LRT Receive
(tip) input
2 LRR Receive
(ring) input
1
6 5 4 3 2
(Front view)
7
8
The cable and plug must be a shielded type to ensure EMC compliance.
If a cable is to be produced to wire into a network trunk connection, the connector on the
network end of the cable must be wired as appropriate for the network-terminating unit
provided.
A 'cross-over' cable is required to connect two E1 cards 'back-to-back', for example, when one
card is to run an exchange end emulation and the other card a user end application. The cable
should be wired as follows.
User End
Exchange End
4 to
1
5 to
2
1 to
4
2 to
5