By acquiring Tele Columbus, Deutsche Telekom would prevent it from falling into the hands of its cable rivals and send a strong signal that it is refocusing on improving its domestic business after the high-profile failure to sell its U.S. unit to AT&T
Cable companies can often offer internet speeds faster than Deutsche Telekom's copper networks, and the former state-owned incumbent has been wary of investing heavily in faster fiber broadband.
By buying Tele Columbus, Deutsche Telekom would also improve its broadband speed in regions where the cable operator is present like Berlin and eastern Germany.
However, the telecom giant will have to fight off Liberty's German unit Unitymedia
Tele Columbus's owners, which comprise funds including York Capital and Golden Tree Asset Management, which took over after the company defaulted in 2010, have mandated Rothschild to organize the sale.
Less than ten funds control the lion's share of the equity, one of the owners said, adding that the investors have agreed not to sell for less than 600 million euros.
The German cable market was once one of Europe's most fragmented, with a proliferation of smaller regional players offering television and broadband services.
But private equity firms and companies like Unitymedia and Kabel Deutschland have restructured the market by buying up smaller companies to create more efficient larger players.
That has put pressure on Deutsche Telekom's fixed-line telephone and broadband business in Germany, which brings in more than two-thirds of domestic sales and shrank by 5 percent last year.
For Kabel Deutschland and Liberty, Tele Columbus would also be a strategic acquisition, helping them to accelerate already strong growth and profits in Germany.
Both have big ambitions. Since its public listing in 2010, Kabel Deutschland has impressed investors, while Liberty has been expanding in Europe.
Acquisition of Tele Columbus would enable Kabel Deutschland, Germany's largest cable operator, to raise the closely watched metric of average revenue per user (ARPU), by selling Tele Columbus clients services such as phone and internet.
The synergies from a deal would be highest for Kabel Deutschland, a source close to the situation said.
It remains to be seen how Germany's competition regulator will view further consolidation in the cable market.
Such deals had long been restrained by regulation that effectively banned mergers among large players. For example, Kabel Deutschland tried to merge with Kabel Baden-Wuertemberg (KBW) and Unitymedia in 2004 to take on Deutsche Telekom, but was thwarted by competition authorities.
But some analysts now believe antitrust regulators are becoming more open to consolidation among cable companies, and they point to Unitymedia's 3.16 billion euro acquisition last year of Kabel BW as evidence.
Kabel BW was Germany's third-biggest cable operator at that time with more than 3.8 million connections or about two-thirds of all households in the German state of Baden-Wuertemberg.
The regulators themselves seem to be sending out mixed signals. Even as the competition watchdog approved the Kabel BW acquisition last year, it was complaining that Germany's three largest cable TV operators already constituted a dominating oligopoly.
Tele Columbus was formerly owned by investor Scott Lanphere's Escaline group and in 2008 almost collapsed under a roughly 1-billion-euro ($1.3 billion) debt load, which Lanphere had dumped on to Tele Columbus while building a cable empire that included German cable group EWT and a majority in rival Primacom.
In the restructuring, roughly 100 creditors agreed to swap part of the debt for equity, pushing out Lanphere. Aligning the interests of the big number of owners is one of the tasks the advisors need to tackle, a person close to the transaction said.
The antitrust question is hard to predict: That's a black box until the very last day, a source said.
All the companies mentioned either declined to comment or could not immediately be reached for comment.
($1 = 0.7590 euros)
(Writing by Leila Abboud; Additional reporting by Peter Maushagen, Harro Ten Wolde, Leila Abboud and Arno Schuetze; Editing by Erica Billingham and Jane Merriman)