A DSC controller is a unit that encodes and interprets DSC messages. In some radios this is built-in and in others it is an external ‘add-on’. There are various classes of DSC controller with varying features. For VHF, Class A is the most complex and Class F the most basic. SOLAS vessels must use a Class A or Class B controller.

The minimum acceptable VHF class for pleasure craft varies depending on the flag of the vessel. Whilst all nations agree that Class D is the ideal standard the higher cost associated with this has encouraged other states to accept lower classes, or develop hybrids. While most of Europe accept Class F for existing equipment (already in the market), Class D is the minimum for new products. The USA has adopted a hybrid of Class D and Class F, known as SC-101.

How will this affect you?

From 1 February 1999 SOLAS vessels are no longer required to monitor the MF distress frequency, 2182kHz. From 1 February 2005 they will no longer need to monitor the VHF distress channel, Ch16.
Thereafter, you may find that the only way to communicate with SOLAS ships is with a DSC equipped radio. Whilst pleasure craft do not have to comply with the SOLAS regulations, the GMDSS does offer many benefits and everyone is encouraged to participate to an appropriate level.

What about Icom?

As one of the world’s leading suppliers of marine radio, Icom are firmly committed to the SOLAS convention, concept of the GMDSS and benefits of DSC for all mariners.

Icom was the first manufacturer to offer a DSC equipped VHF radio specifically for the pleasure market (IC-M58). This radio was equipped with Class C DSC and when this specification was withdrawn by the IMO, Icom quickly replaced the model with the Class F compatible IC-M59 Euro, later adding the IC-M127 Euro. The USA versions of these radios are SC-101 compatible. We have also developed the MF/HF IC-M710GMDSS radio and GM-110DSC Class A DSC controller for larger pleasure craft, fishing vessels and SOLAS ships.

Globally, VHF DSC for pleasure craft is in its very early development stages and is a very small market for a manufacturer like Icom. The decision by the IMO to extend mandatory Ch16 VHF monitoring for SOLAS vessels has also reduced the impetus for users to upgrade, whilst the US has said that VHF DSC infrastructure will not be on-line until at least 2008. This combination of factors does not make the market very attractive and accordingly, equipment is relatively expensive at this time. For example, present non-Icom, Class D equipped VHF radios cost in the region of £650, whilst Icom Class F and SC-101 radios for other markets can be purchased for about £375.

However, from the start of 2001 all VHF fixed transceivers sold in Europe must be DSC compatible (e.g. with a DSC interface or built-in Class D controller). Recent regulations have established Class D (sometimes referred to as MPT1279 or EN301 025) equipment as the minimum acceptable for non-SOLAS vessels to successfully participate in the GMDSS.

Subsequently, Icom is now developing an appropriate product, to be available well before the 2001 deadline.

What should you buy?

Essentially, you have three choices:

1. If you need a new VHF radio and will either replace it by 2005 or wish to wait for DSC prices to fall, consider a non-DSC compatible model such as the Icom IC-M59 Euro or Icom IC-M127 Euro.

2. If you need a new VHF radio, to remain in service through 2005, you should consider a DSC compatible unit. You may wish to delay purchasing until Icom has announced its new product. You can also wait until nearer 2005 before purchasing the DSC controller. The DSC protocol is ‘open’ and this means that DSC controllers from any manufacturer should be compatible.

3. If you have a working VHF and no immediate reason to change you might consider waiting for the new Icom product or for the prices of other DSC compatible models to fall.