City Council is slated to vote Thursday on a plan to bring two digital billboards to Center City. The bill, sponsored by Councilman Mark Squilla, allows for "urban experiential displays" near the Convention Center and Reading Terminal Market.

Squilla has said there is widespread support for the bill, citing 300 letters sent to his office and more than 100 people expected to speak in favor of the digital billboards.

A review by The Inquirer of the typed letters shows they are identical and that the signatures are in the same cursive font. They were all in a binder assembled by Catalyst Outdoors, the Malvern advertising firm that would erect and own the two boards.

PlanPhilly first reported on the letters, the text of which matches an online petition by "The Philadelphia UED Project."

Many of the form letters are signed by people who live outside Center City. Signers of the online petition live as far away as Singapore, although most said they are from Pennsylvania and New Jersey.

Council members Wednesday still were deciding how they will vote. "I'm not 100 percent sure," Republican at-large Councilman David Oh said. "I don't believe it will be as grotesque as some are making it out to be."

Some staffers reported phones ringing off the hook as constituents called in against the bill.

The opposition - led by Scenic Philadelphia, which has opposed large billboards and displays - has called the displays eyesores and pushed for their dismissal.

Scenic Philadelphia's director, Mary Tracy, has encouraged Council to look at Center City not as Squilla's district but as "everyone's downtown."

Thaddeus Bartkowski, owner of Catalyst, has given political donations totaling nearly $10,000 to several Council members, including Squilla.

Frank DiCicco, a former councilman representing Squilla's district, now is a lobbyist for Catalyst.

Squilla said the displays would serve a public purpose: 30 percent of content must be noncommercial.

There is also a financial incentive - Catalyst must pay $5.2 million per board to three local nonprofits: Avenue Renaissance North, Friends of Rail Park, and Reading Terminal Market.

The bill's zoning originally included part of Center City in Councilman Kenyatta Johnson's district, but Johnson asked that his district be removed after hearing complaints.

The design plan for the display outside Reading Terminal is a hand holding a globe. A more traditional square installation would sit outside the Convention Center. If the bill passes, both designs still would have to be approved by the city's Art Commission.

The boards are bound by strict size and brightness regulations. They can't exceed 58 feet if attached to a structure, or 45 feet if freestanding, and the video display must be between 1,500 and 2,500 square feet.

The signs would be able to stay lit between 6 a.m. and midnight, or at other times approved by the Planning Commission.