1. When do I need a cross over cable?

There are a number of scenarios that could lead the requirement of a crossover cable. The most common one is when you are connecting a piece of equipment that is DCE to one of Metrodata's units which is also a DCE.

2. How do I configure a DC3000?

Configuration for the DC3000 is done by way of Dip Switches located on the base of the unit.

You can refer to the Manual on the CD shipped with the DC3000 unit or register on Metrodata's web site and download the  DC3000 Manual

3. What Clocking mode should I use?

Clocking modes vary from application to application but in most straight forward applications i.e a simple point to point connection, the ideal clocking configuration would be to have one unit set to INTERNAL (Master ) supplying the clock and the other unit set to LOOP (Slave ) which would slave the clock back to the circuit.

4. What is the E1 to X.21 DC3000 converter Dip Switch setting for BT MegaStream?

The DC3000 has two banks of dip switches, the first bank addresses testing, clocking and timeslot allocation. The second bank addresses bandwidth allocation, timeslot 16 signalling, CRC4 and interface selection as BNC or RJ45.

The switches should be set to the following:

This will provide internal clocking, starting at timeslot 1 with a bandwidth of 1024kbps, CRC4 enabled and BNC connectivity selected.

5. Can I interface the KIV-7M to a DS3

Yes. Metrodata currently have a dual unit solution for interfacing LVDS / EIA-644 on the KIV-7M to a Clear Channel DS-3 Circuit. This involves the Metrodata BC1000 and the DC3445 in a 1U Rackmount. Visit the following page more information on KIV-7M Interfacing solutions.

6. What is LVDS (EIA644)?

LVDS (EIA-644) - Low Voltage Differential Signalling; 3.5mA drive, at 655Mbps max, Point-to-Point

EIA-644-A defines the basic electrical characteristics of the LVDS interface. LVDS is typically found on Satellite Modems and new Dual Channel Encryption Equipment like the KIV-7M and the KIV-19M. Metrodata specialise in interfacing LVDS to more common interfaces such as HSSI, DS-3 BNC, Fiber and Ethernet. Click here for more information regarding Metrodata's LVDS EIA-644 products.

7. Is there any overhead transporting E1 over Satellite?

Metrodata utilises the APSAT Platform for transporting up to 32 x E1 over satellite on a range of different satellite serial interfaces. Typically the overhead of using the APSAT comes from the ATM cell overhead.

8. Can ISDN and QSIG protocols be transported over fibre?

Metrodata's FC range of Fibre Converters are transparent to these protocols. QSIG is a signalling protocol which is carried within the E1 payload (FC1000 product)

9. What types or fibre can I use?

Multimode or Single mode are the common types
Multimode is less expensive and is used for shorter distances typically within a building.

Wavelengths are typically 850mn, 1300/1310mn and 1550nm

10. Where can I buy cables or Fibre?

You can source cables from any good cabling company

For UK:

Servicepower Ltd (Shipley) 01274 207500
Fibre Technologies (Crowthorne, Berks) 01344 752222
Mediatron (Guildford Surrey) 0870 9978899

11. Can I use a DC1000 or DC1200 on a fractional service?

The DC1000 and DC1200 converters are used for a clear channel unframed E1 (2048kbps) service.

If the service is fractional (framed) then a DC3000 or DC3200 is required, Metrodata also offers a range of SNMP Managed Converters.

12. What distance can Metrodata's Fibre converters drive?

The distance is dependent on a number of factors, signal attenuation should be calculated according to the loss budget of the fibre quality, number of joins, other connections etc.

For Metrodata's products have a typical guide distance of:

Multimode fibre 2 - 5km
Single mode Short Haul fibre 15 - 40km
Single mode Long Haul fibre 40 - 70km

Each Data Sheet shows the respect Optical Loss Budget figures (dB)

13. What product do I need to transport Ethernet over E1?

For the transportation of Ethernet LAN over E1 Metrodata offers the WC1000.
One unit is placed at each end of the E1 link and this effectively extends your LAN, typically from building to building or across campus.

14. Is IP over E1 the same as E1 over IP?

IP over E1 is different from E1 over IP

E1 over IP (often referred to as TDM over IP) is a newer technology whereby Leased Lines can be replaced by an IP network that has adequate Quality of Service to recover / reconstruct the clocking required for this technology to operate.