Symmetricom Inc. (Nasdaq: SYMM), maker of a timing element key to the emerging modular cable modem termination system (M-CMTS), is having trouble predicting when cable operators plan to shift gears and adopt the new platform.

Although Symmetricom remains "on track" with field and lab trials with operators, "we cannot forecast the pace at which MSOs will cut over to modular CMTS equipment," company president and CEO Thomas Steipp said Thursday during a conference call about the company's fiscal fourth-quarter results. (See Symmetricom Reports Q4.)

Symmetricom, he said, has started shipping its new cable product, the Time Creator 1000. For the year, those shipments have generated about $900,000 in revenues, with most of that activity happening in the last two quarters.

The modular version of the CMTS is designed to separate out functions -- including upstream and downstream capacity -- that are typically tied together in the same CMTS chassis. This way, operators can scale downstreams and upstreams based on demand.

To keep the clocks of those separated elements synchronized, CableLabs has developed a Docsis Timing Interface Server (DTIS) spec. Last August, Symmetricom's Time Creator 1000 became the first element of the M-CMTS architecture to win approval from CableLabs. (See CableLabs OKs First Modular CMTS Element .)

While operators may use the M-CMTS to support Docsis 3.0, a spec that uses channel bonding to produce shared speeds of more than 100 Mbit/s, it is not required. CMTS vendors are also supporting Docsis 3.0 in integrated chassis.

Few MSOs have yet deployed, or announced big plans to deploy, the M-CMTS architecture. However, vendors such as BigBand Networks Inc. (Nasdaq: BBND) have disclosed some limited M-CMTS deployment activity, most of it happening overseas. (See M-CMTS: Turning Japanese and BigBand Goes Dutch With M-CMTS.)

Among U.S. MSOs, Comcast Corp. (Nasdaq: CMCSA, CMCSK) has reportedly questioned the current business case for making the move to the M-CMTS. Comcast instead will leverage its extant base of integrated CMTSs to embark on initial Docsis 3.0 trials. (See Comcast Preps Docsis 3.0 Trials.)

— Jeff Baumgartner, Site Editor, Cable Digital News