MANILA, Philippines - Field tests conducted by the Commission on Elections (Comelec) on Friday morning were hampered by weak cellular site signals in two areas in Taguig City.

Initial reports said the Precinct Count Optical Scan (PCOS) machine at the Maharlika Elementary School failed to transmit counted votes to the municipal board of canvassers and the poll body's central office.

A radio dzMM report said that the election officers changed SIM cards for 40 minutes, but still failed to complete the transmission.

The Comelec, however, clarified that the PCOS was able to eventually transmit counted votes to the servers at municipal level and to the poll body's central office in Intramuros, Manila.

It said the initial try using Smart telecommunication's mobile network signal failed, but they were able to eventually send data to all the servers using a Globe telecommunication's SIM card.

In the field test conducted at the Taguig City Elementary School, the PCOS machine was able to send counted votes to the city level, but failed to transmit more data to the central server at the Comelec's main office using a Globe SIM card.

Comelec officers conducting the test changed the Globe SIM card with a Smart SIM and then repeated the process. With the change, the PCOS machine successfully transmitted counted votes to all servers within minutes.

The field tests results conducted in Taguig were almost the same as the results the Comelec had during the initial field tests in 10 selected sites nationwide.

Palace: Don't panic

More concerns about the full automation of May 10 national elections have been raised due to the mixed results of the initial field tests.

Despite the glitches, Malacañang said it's still confident with the Comelec's capability to successfully implement the May 10 elections' full automation.

"Huwag naman tayong mag-panic na iiwan natin mag-isa ang Comelec (Let us not panic and abandon the Comelec)," presidential spokesman Gary Olivar told reporters at Malacañang.

He said that if the full automation of the May 10 elections fails to push through, Malacañang is still confident that the Comelec can still conduct clean elections.

"We stand by their authority and integrity," he added. – Reports from Dennis Datu, radio dzMM, Ina Reformina and RG Cruz, ABS-CBN News